1. Introduction
[1.1] With the emergence of Web 2.0 and the rise of social tagging systems on online platforms, users have a new degree of control over the classification of online resources. Rather than adhering to strict classification guidelines used by information professionals, users on these platforms can assign tags to resources based on their own interpretation by using folksonomies. Folksonomies are informal, nonhierarchical classification systems consisting of collaborative, user-generated content for the purpose of information organization (Neill Hoch 2018; Bourlai 2018; Zarin 2018). Traditionally, information professionals focus on classifying the contents of a resource, but folksonomies have an expanded functionality that allows for the inclusion of differing perspectives related to a resource through user involvement. Users require no information classification training to contribute to folksonomies, which expands online collection curation beyond the realm of information professionals. Folksonomies also differ from traditional classification systems in that they allow for, and sometimes even embrace, the inclusion of authorial voice, or tags containing user-specific information or commentary, from participating users on social tagging websites.
[1.2] The primary function of tags on online platforms is to accurately and succinctly describe resources using keywords or short phrases for the purposes of information discovery. However, more expressive tagging practices have emerged as an unexpected result of folksonomies and social tagging systems. Information scholars diverge on the usefulness of tags containing user-specific information and authorial voice. One study on the ability of user-generated tags to enhance access to literary works excluded all personal tags from the sample analyzed, which included opinion-based terms like "favorite" or "boring," indicating that these tags could not contribute to information discovery (DeZelar-Tiedman 2011). Other studies have pointed to ways in which personal information can contextualize and enrich discovery (Feinberg 2011a, 2011b; Rorissa 2010).
[1.3] Expressive tagging, as well as the inclusion of authorial voice in tagging practices, has become popular in online fandom spaces in the form of commentary tags, which developed through the adaptation of folksonomy-based social tagging to incorporate more expressive elements alongside descriptive tags. Commentary tags often reflect the user's emotional response to a post, including phrases such as "I loved this so much." Incorporating comments into tags evolved into common practice on Tumblr due to the lack of commenting functionality on the platform, which is the focus of section 3 in this article (Price and Robinson 2021). Fans in particular embraced this practice, with one study finding the highest usage of commentary tags on Tumblr attached to fandom-related posts (Bourlai 2018).
[1.4] Although popularized on Tumblr, commentary-style tags have become a recognizable fandom practice across platforms hosting fan communities, despite some pushback from fans. Of particular note is their presence on Archive of Our Own (AO3), which offers functionality such as sections for author’s notes, removing the need for tags to serve as a vehicle for communication and expression. The site design allows for free tagging, and AO3 has stated their refusal to moderate these tags (OTW 2012b). However, some users on the site, echoing concerns of information professionals regarding personal information in tagging systems, have pointed to drawbacks related to search and discovery, as well as other concerns. Fans continue to discuss their tagging preferences on various platforms, which I explore in section 4 of this article. Regardless of the controversy, the practice of author expression and commentary through tagging on AO3 persists.
[1.5] While descriptive tags are necessary for efficient search and discovery, the practice of commentary tagging on AO3 expands the functionality of online tagging to incorporate creative and expressive elements. In section 5, I analyze commentary tags and fan comments on a work of AO3 fan fiction to argue that commentary tags can add value by (1) drawing interest toward a fic, (2) providing context about the content of a fic, (3) managing user expectations, (4) supporting community spaces and practices, (5) allowing for communication between authors and readers, and (6) preserving elements of online fandom culture. Additionally, though it is seemingly antithetical to conventional information systems that prioritize limits on bias, I explore in section 6 how the expanding use of tags in fandom spaces in these six areas could have implications for the inclusion of authorial voice through tagging in information discovery systems outside of fandom as well. I argue that while users should use commentary-style tags judiciously and in conjunction with tags geared toward search and discovery, these six areas demonstrate the potential for commentary-style tagging as an enhancement to descriptive tags, rather than a detriment to search and discovery.
2. Methodology
[2.1] I analyze content posted publicly by users on Tumblr, AO3, and other public websites in order to gauge fans' opinions and practices regarding commentary tagging. AO3 released two news posts in 2012 in regard to tagging on AO3 and controversy over tagging practices, but commenting was restricted on both posts. In order to gauge fans' opinions on tagging practices around the time of these news posts, I reference several threads related to this subject on LiveJournal, which hit its peak of fandom usage in 2011–2012 (Fiesler and Dym 2020). Fanlore's page on the "AO3 Tagging Policy Debate" helped identify some LiveJournal threads in which this subject was discussed (https://fanlore.org/wiki/AO3_Tagging_Policy_Debate). Additionally, to gain a deeper understanding of more recent fandom opinions and practices related to tagging, I also reference fan-created AO3 tagging guides that include a range of opinions and suggestions regarding commentary tagging. Posts and guides were selected to represent a range of user opinions for contextual purposes rather than to provide a comprehensive analysis of user opinions and practices.
[2.2] Scholarship on ethics in fan studies notes that even when posting on open platforms like Twitter or Tumblr, fans may not expect their content to reach an audience beyond their followers or fandom community, and it cautions researchers to consider this while pulling data from platforms (Booth and Williams 2021; Fiesler and Dym 2020). Previous editors of Transformative Works and Cultures Karen Hellekson and Kristina Busse also strongly encouraged researchers to ask fans for permission before referencing their works or posts (Hellekson and Busse 2009). In keeping with these recognized values and ethics in the field of fan studies, for all content referenced and/or quoted from these websites, permission was obtained from the author of the post or fan fiction to include quotes and screenshots of their content in this paper with their usernames cited; this excludes anonymous posts and accounts lacking a method of contact, for which obtaining permission was not possible.
3. Community-developed tagging practices on Tumblr
[3.1] Tumblr is a social media blogging platform that was founded in 2007 by David Karp and later acquired by Yahoo in 2013 (Bourlai 2018; Price and Robinson 2021). Though it allows for long-text posts, site users primarily share multimedia content, making the tagging system instrumental to the searching and discovery of resources. Tumblr puts no limit on how many tags can be applied to a post, though only the first twenty can be searched, nor does it impose any restrictions in tag formatting, though users can only add tags to resources they have created or reblogged (Bourlai 2018; Price and Robinson 2021).
[3.2] Tags occupy an even more central role on Tumblr as, unlike other popular social media sites, it did not have a traditional commenting function for most of its history. Instead of commenting directly on a post, users had to reblog the post to add their comments. On the whole, users opted to put their comments in tags instead of cluttering the original post with reblogs containing commentary, and the trend persists today despite the eventual development of a reply feature (Bourlai 2018; Price and Robinson 2021; Neill Hoch 2018). This community-developed practice on Tumblr has created a unique style of tagging that centralizes the tags as part of the blog posts themselves and relies heavily on commentary tags as a form of communication.
[3.3] Due to this community-developed practice, Tumblr tags serve a dual purpose as both an information organization system through the use of descriptive metadata tags and as a vehicle for personal commentary and communication with other users. Descriptive tags provide information about the content of a post and aid in search and discovery on the platform. For example, tagging a post about the TV series Buffy the Vampire Slayer (1997–2003) would likely include descriptive tags such as "btvs" or specific character references; this clarifies the content of the post for users who may not be aware of the series. Studies from Bourlai (2018) and Price and Robinson (2021) have shown that users on Tumblr primarily use tags for descriptive metadata and keywords but did also find significant numbers of commentary tags.
[3.4] Unlike many prominent social media sites, Tumblr allows spaces and special characters in its tags, resulting in commentary tags comprising phrases or sentences that are generally three times longer than descriptive tags (Bourlai 2018). Commentary tags are part of the post and can even be considered "similar to footnotes, meta-commentary, or indeed, paratext, qualifying or framing the main content of the post" (Price and Robinson 2021). Bourlai (2018) identifies three discourse functions for commentary tags on Tumblr: opinion, reaction, and asides. Opinions express a user's thoughts, remarks, or observations about the content of a post; reactions convey a user's emotional response to a post; and asides are comments indirectly related or nonrelated to the content of a post (Bourlai 2018).
[3.5] Commentary-style tagging is especially evident in fan communities on Tumblr. In a comparison between posts from Tumblr's "Trending" page and fandom posts, Bourlai (2018) found that commentary tags are three times as frequent in fandom posts and that fans are more likely to write asides in their tags. As Stein (2018) notes, "Each interface used by fans develops and maintains its own community norms, expectations, and limits of code and culture" (86). On Tumblr, putting comments in tags rather than reblogging commentary is not only common practice but understood etiquette that is strongly encouraged by other Tumblr users (Bourlai 2018).
[3.6] Commentary-style tagging serves several important functions for fans on Tumblr. First, commentary tags are the primary method of communication between fans on Tumblr and allow for creative expression (Price and Robinson 2021). Each type of commentary tag carries the voice of the user with some underlying emotion, unlike descriptive tags, which are most often neutral. These types of tags, while contributing little to search and discovery functionality, also foster community-building on Tumblr by adding an extra layer of description related to the user's identity (Price and Robinson 2021; Neill Hoch 2018). By allowing for communication, expression, and community building, commentary tags in fandom spaces prompt deeper engagement with other users and tagged resources.
[3.7] As an example, Tumblr user kpopmasterlists tagged a post containing fan fiction "ok well this fucked me up in the best way oh my god" (https://kpopmasterlists.tumblr.com/post/165464113834/to-promise-7). Unlike a descriptive tag that details the content of the fan fiction, this commentary tag conveys information about the user's reaction to the fan fiction in the user's voice. This style of tag opens a dialogue with other users and carries more of an emotional impact than simply descriptively tagging the fan fiction as "sad." While perhaps not useful for search and discovery purposes, this commentary tag instead prompts curiosity and deeper engagement from other users, possibly bringing the content of the post to a wider audience.
[3.8] Many fan users on Tumblr use a combination of descriptive and commentary tags on a post. One Tumblr user tagged a post regarding the ending of the Broadway musical Hadestown (2006) with a simple combination of one descriptive tag, "hadestown," and one commentary tag, "screaming crying etc" (https://apalatablevastness.tumblr.com/post/689359491220881408). This combination gives other users context—the Broadway musical Hadestown—and then a deeper level of engagement through the commentary as it notes an intense reaction that could influence another user's experience. The tone of the commentary tag further suggests that someone familiar with this fandom could easily relate to the sentiment, "screaming crying etc," which can aid in building a sense of community around fandom experiences.
[3.9] While common practice in fandom spaces on Tumblr, commentary tags have prompted some discussions on their possible detrimental effects on search and discovery on the platform, particularly after Tumblr's introduction of a commenting feature in 2016 (Carman 2016). This update to Tumblr's functionality means that tags are no longer required for communication between users. However, users still rely on commentary tags as a way of communicating with followers and see value in this practice, as evidenced by the studies by Bourlai (2018) and Price and Robinson (2021) that found high usage of commentary tags even after the introduction of a commenting feature. The user cyle on Tumblr advocated for some balance between this popular platform practice and functional search and discovery, posing the question, "How do we preserve all of this awesome unique behavior without stopping the viral spread of content through reblogs?" (https://cyle.tumblr.com/post/710445389346734080/the-problem-of-commentary-in-the-tags). As of now, no further changes have been made on Tumblr to account for this user practice while keeping descriptive tags separate for search and discovery purposes, and users continue to communicate through tags. This dual-tagging method that has become established fandom practice on Tumblr has permeated other fan-adopted and fan-created platforms as well, leading to more vehement discussions surrounding commentary tags on fan platforms.
4. Drawbacks and controversy
[4.1] Though popularized on Tumblr due to the platform's initial commenting constraints, commentary tags migrated with fan communities to platforms like AO3. This migration of practices across platforms is common in fan communities, resulting in echoes of past fandom practices in modern fan behavior on platforms (Fiesler and Dym 2020; Stein 2018). While overarching values and basic practices are incorporated into new platforms with few issues, the particulars of etiquette can vary widely by platform and sometimes within specific fan communities on the same platform (Dalton 2012).
[4.2] Because of this, while commentary tagging exists on AO3, it is not the accepted and strongly encouraged practice that proliferates on Tumblr. Fan debates over the inclusion of commentary tags on AO3 fics, particularly in the early years of the archive in 2011–2012, warranted a Fanlore entry on the "AO3 Tagging Policy Debate" (https://fanlore.org/wiki/AO3_Tagging_Policy_Debate). Conversation within fan communities regarding these practices and their repercussions often took place on Tumblr and LiveJournal threads, like those from the anonymous account Fail Fandom Anon (FFA). To give an idea of scope, I will examine five separate FFA threads from 2011–2012 debating the use of commentary tags on AO3, each of which generated over 5,000 comments. More recent examples of fans' opinions on AO3 tagging can be found in user-created AO3 tagging guides. The conversation within these five FFA threads on AO3 tagging practices and the suggestions included in tagging guides present a range of opinions. Though not all negative, fans express some valid concerns regarding the inclusion of commentary tags on AO3 fics. Fans' arguments against commentary tagging on AO3 include general annoyance at having to read through long blocks of text to find the descriptive tags on works, creation of search and discovery issues, and concerns for added burdens on AO3's volunteer tag wranglers and servers.
[4.3] Some users on FFA expressed frustration when fan works on AO3 have "walls of tags" that make it difficult for readers to determine the central concepts in a work (https://fail-fandomanon.livejournal.com/31204.html?thread=140178148#t140178148). Flooding the reader with too many tags prevents them from succinctly gauging the content of a work, and commentary tags can potentially compound the issue. One FFA user stated that they "don't read fic with walls of tags attached" and "avoid wall tagging" on their own fics, so excessive tags can prevent some readers from engaging with fics (https://fail-fandomanon.livejournal.com/31204.html?thread=140178148#t140178148).
[4.4] In August of 2021, AO3 limited users to seventy-five tags per work in response to the infamous fan work Sexy times with Wangxian (STWW) that had over 1,700 tags assigned in February 2021 (OTW 2021; Virtual1979 2021). The fan fiction caused usability issues for users on AO3 across fandoms due to the expansive nature of the tags, especially when reading on mobile devices. Some frustrated users even implemented creative work-arounds to avoid seeing the fic in their search results by using Chrome extensions and site skins (Romano 2021). Interestingly, the author of STWW used nearly all descriptive tags on the work, and there are only a handful that could be classified as a commentary tag, such as "You Have Been Warned" (Virtual1979 2021). As this example demonstrates, excessive use of descriptive or commentary tags can easily overwhelm readers and should be used in moderation.
[4.5] Users on FFA frequently cited search and discovery issues to discourage use of commentary tags on AO3. They invoke commentary tags' "totally useless" contributions to search and discovery on AO3 and insist on "informative and concise" tagging practices (https://web.archive.org/web/20220218184344/https://fail-fandomanon.livejournal.com/22095.html?thread=98986831) (https://web.archive.org/web/20220218190133/https://fail-fandomanon.livejournal.com/31498.html?thread=143584266). In the opinion of one dissenting user on FFA, "Those tags are actually designed to help you find fics and identify the content. It's not your Tumblr" (https://fail-fandomanon.livejournal.com/31481.html?thread=142181625#t142181625). This implies a concern with commentary tags inhibiting search and discovery on AO3 but does not apply the same concern to Tumblr. Similarly, some comments suggest that the controversy lies in translating practices to a new platform, rather than a stance against commentary tags overall. As one user noted, "I really, really actually like rambling stream-of-conscious tags like this. Only not on AO3. Save that for tumblr, guys" (https://fail-fandomanon.livejournal.com/31481.html?thread=142181625#t142181625). One user-created AO3 tagging guide warns that commentary tags can prevent interested readers from finding a fic:
[4.6] The Archive tags really aren't meant for ramblings. These ramblings can actually prevent your fic from showing up in the correct tags. For example, if an author writes, "eventual romance maybe idk we'll see" as a tag, the real tag–"Eventual Romance"–won't be assigned to this fic, and that's an entire portion of its potential audience that is lost! ("AO3 Tagging System" 2020)
[4.7] Several posters to these five FFA threads mention that these tags actually belong in the author's notes section, such as one user's comment that "tags are tools for searching, being idiosyncratic or funny about what the fic's about is what you do in notes at the beginning or end of the fic" (https://fail-fandomanon.livejournal.com/31204.html?thread=140178148#t140178148). A tagging guide from ErinPtah (2013) on AO3 similarly advises putting Tumblr-style tags in the summary or author's notes. This emphasis on information discovery on AO3 in comparison to Tumblr's lax tagging culture may stem from the fact that Tumblr is an open-tagging platform where tags contribute little to discovery due to lack of organizational structure. Alternatively, AO3 prioritizes discovery through its tag wrangling system, and users may moderate their tagging practices to support that system.
[4.8] Part of the frustration over commentary tags on AO3 stems from misunderstandings regarding their negative impact on the website, including their contributions to tag wrangling workload and added strain on server capacity. AO3's hybrid tagging system relies on volunteer labor from tag wranglers to standardize and organize tags on the backend to increase discoverability of fan works in the archive. Wranglers create hierarchies of tags to link concepts together and to link synonyms and alternative wordings. For example, the "merpeople" meta tag links to "mermaid," "merman," and "merfolk" so that searching any of those terms also brings up the others (Fiesler, Morrison, and Bruckman 2016). This practice of merging synonyms in tags is called "syn-ing." Wranglers review and organize tags in four categories: Fandoms, Characters, Relationships, and Additional Tags (Freeforms), which collectively generated 500,000–750,000 new tags per month in 2018 and has only grown since (Zarin 2018).
[4.9] AO3 users, cognizant of this finite source of volunteer labor, aim to avoid adding to wranglers' workload by moderating their tag usage. One anonymous user on FFA posted, "I'm sometimes tempted to use the freeform tags as author's notes, but then I think of the tag wranglers and can't quite bring myself to do it" (https://fail-fandomanon.livejournal.com/31204.html?thread=140178148#t140178148). Two tagging guides also advise avoiding commentary tags in part to "cut down on wrangler workload" (ErinPtah 2013) and "for the sake of the poor Archivists who have to sort through all those meaningless ramble tags!" ("AO3 Tagging System" 2020).
[4.10] However, AO3 confirmed in news posts that commentary tags "do not interfere with the wrangling of non-freeform tags" and "put almost no strain on the servers" (OTW 2012a, 2012b). A post from AO3's official Tumblr account commented further that Tumblr-style tags "can just be chucked into the metaphorical void that holds the non-canonical or unwrangleable tags" and clarified that using them "doesn't create more work for the wranglers than the simple act of wrangling already does" (https://ao3org.tumblr.com/post/58351045314/tumblr-tagging-and-why-its-a-problem-on-non-tumblr).
[4.11] The AO3 News posts also clarify that excessive tags were not responsible for the "Death of the Filters" incident, when, due to rapid site growth, tag filtering was disabled on AO3 for four months in 2012 during a server upgrade (OTW 2012a). These comments from AO3 make it clear that commentary tags do not adversely affect the tagging system or server capacity for the platform. The Wrangling Guidelines for additional tags even include "commentary" as an example of tag use along with tropes and warnings (Archive of Our Own n.d.b). AO3 stands by the fact that they do not alter creator tags and welcome creator expression within their policy limits.
[4.12] Fans have some valid concerns regarding inclusion of commentary tags on AO3 fics. Adding too many commentary tags, especially in place of accurate descriptive tags, would impede efficient search and discovery and cause some users frustration when having to parse them. Some fans have looked to a compromise similar to what cyle suggests on Tumblr: a way to keep this fandom practice intact while separating tags meant solely for search and discovery. As one user on FFA poses, "Perhaps what we need is a non-freeform tagging field everyone can see and a freeform tagging field you can set your preferences to never see if you hate them. Then everyone would be happy!" (https://web.archive.org/web/20220218184344/https://fail-fandomanon.livejournal.com/22095.html?thread=98986831). No functionality modifications like this have been implemented on AO3 aside from the tag limit. However, if used in moderation and in conjunction with descriptive tags, commentary tags on AO3 and in other information systems could enhance rather than hinder information discovery, as I explore in the next section.
5. Commentary tags on Archive of Our Own
[5.1] The design of AO3's tagging and wrangling system purposefully creates space for user expression, including through the use of commentary tags. The Wrangling Guidelines emphasize that the priority is to "standardize canonical tags and synonym relationships as much as possible, while keeping in mind that different fandoms (and people) organize information about their fandoms differently" (Archive of Our Own n.d.b). AO3 does not restrict users to any terminology, formatting, or type of tags, and tag wranglers do not change the tags during the tag wrangling process in order to "respect the distinctions users are making with their tags" (Archive of Our Own n.d.a). This policy allows for, and even encourages, user expression in tagging practices.
[5.2] On AO3, open tagging operates similarly to Tumblr tags in that they serve more than information discovery purposes. In studies of tagging behavior on AO3 published by Price and Robinson (2021) and Gursoy, Wickett, and Feinberg (2018), both found that descriptive-style tags were the most popular tag type overall, followed by commentary-style or expressive tags. Descriptive tags resemble traditional classification and metadata terms; they are usually one word, present for the sake of information discovery, and indicate elements of the story such as setting or genre. This reinforces the primary function of tags as vehicles for description and discovery, with commentary tags serving a secondary purpose.
[5.3] There is some overlap between descriptive and commentary tags on AO3 due to the functionality of the wrangling system. Commentary-style tags can be wrangled as canonical tags, especially if used by many authors. For example, the commentary tag "Loki Needs a Hug (Marvel)" is not only a statement about the character Loki but also a reference to aspects of the story that readers can expect in the fic. The tag is applied to nearly 5,000 fics on AO3 and can be used by readers interested in that specific characterization to find relevant fics (https://archiveofourown.org/tags/Loki%20Needs%20a%20Hug%20(Marvel)/works). This is an example of a commentary tag serving a descriptive purpose, indicating that these tags on AO3 can contribute to search and discovery, in addition to their other purposes explored below.
[5.4] The design of AO3 does not require the use of commentary tagging to engage in communication, expression, or community-building as it does on Tumblr. AO3 has commenting features and options for free text to preface the works in author's notes, but users choose to carry over this practice to AO3 regardless. In some cases, the authors could have translated their commentary tags to descriptive tags but were "committed to the conversational style of tagging" (Gursoy, Wickett, and Feinberg 2018). There are several potential benefits to adding commentary tags on AO3 fics, including (1) drawing interest toward a fic, (2) providing context about the content of a fic, (3) managing user expectations, (4) supporting community spaces and practices, (5) allowing for communication between authors and readers, and (6) preserving elements of online fandom culture.
[5.5] AO3 users have expressed appreciation for commentary tags as a way of generating interest in a fic, including on the FFA threads explored in the previous section. One user posted on FFA that they "like author's note-like tags, and they make me more likely to read a fic. Which I guess is why people keep using them. Sorry, anons who hate it" (https://web.archive.org/web/20220218184344/https://fail-fandomanon.livejournal.com/22095.html?thread=98986831). An anonymous poster on FFA who argued against inclusion of commentary tags admitted that after reading them for one fic, they "LOLed, and really kind of want to read this fic now. SO CONFLICTED" (https://fail-fandomanon.livejournal.com/31481.html?thread=142181625#t142181625).
[5.6] This function of commentary tagging echoes the use of these tags on Tumblr. Adding conversational-style tagging, usually in a humorous way, draws interest to the tagged resource from other users in a more effective way than simply using descriptive tags. An AO3 tagging guide created by user Lililoveschampagne on Reddit in 2019 even included "humour or meta-commentary" as a suggested tag category, with the caveat of not using too many (https://www.reddit.com/r/FanFiction/comments/dwu4f5/an_incomplete_guide_to_ao3_tags/). Additionally, tags on AO3 are viewable from the preview of a fic, giving authors a space to provide details about their story in their own words to attract browsing users. This offers an advantage over adding these comments to the author's notes section, which is only viewable after opening a fic.
[5.7] As on Tumblr, users on AO3 often pair commentary tags with descriptive tags to provide additional context and enhance users' understanding of the described resource. The AO3 fan work Charting Stars On A Stained Glass Ceiling (2021) written by mornmeril includes commentary tags that exemplify this functionality on AO3 (figure 1). Several commentary tags on this fan work clarify canonical descriptive tags, such as expanding on the descriptive tag "Illnesses" with the commentary tag "(brought on by love potion/spell)" (mornmeril 2021). The author had already included the descriptive tag "Love Potion/Spell" but also opted to highlight the connection between the two descriptive tags with a commentary tag. Similarly, the author clarified the descriptive tag "Mildly Dubious Consent" with the commentary tag "(due to said love potion/spell)" to emphasize the connection between the concepts (mornmeril 2021). Using the commentary tags to enhance the descriptive tags in this way gives users a better understanding of the content of the fan work than is possible by applying only descriptive tags.
Figure 1. Screenshot of tags attached to AO3 fan work Charting Stars On A Stained Glass Ceiling. Completed July 22, 2021. See full fan work: https://archiveofourown.org/works/32454433/chapters/80478619.
[5.8] Authors on AO3 can manage reader expectations through commentary tags by preparing a reader for the contents, warnings, and tone of a fic. The author of Charting Stars On A Stained Glass Ceiling employs commentary tags in this way. For example, the tag "UST" (unresolved sexual tension) is elaborated on with "so much UST" and "don't worry tho they resolve it eventually" (mornmeril 2021). This serves to reassure potential readers that the descriptive tag "UST" does not indicate that the romantic pairing of the story remains unresolved, as it may imply. Similarly, the author opted to use commentary tags to softly introduce concepts of the story. For example, they used the tags "background politics" and "some violence" in place of descriptive canonical tags like "Politics" or "Violence," which qualifies and de-emphasizes their role in the fic while still alerting users to their inclusion in the story.
[5.9] Commentary tags can also support community spaces on AO3 through fandom-specific references. For example, some of the commentary tags applied to this fan work convey to the reader elements of the story by tapping into shared fandom knowledge in a way that descriptive tags cannot. This fan work was written based on the BBC television show Merlin (2008–2012). Two of the commentary tags reference specific characters and characterizations of which the author likely expects a potential reader within the Merlin fandom to have a basic understanding. The two commentary tags give readers an idea of the relationship between two canonical characters, Merlin and Will, by saying "Will doing his best to expose Merlin" and "but Merlin loves him anyway" (mornmeril 2021). These are fandom-specific tags and even hint at specific characterization, which descriptive tags could not have accurately described for the reader.
[5.10] The conversational nature of commentary tags allows for an avenue of communication between authors and readers. Aside from story elements, the author of this fan work further engages with the reader by providing behind-the-scenes information on the writing process. The commentary tags detail backstory on the fan work—"working title for this was Irresistible Cupcake"—and humorously express the author's writing experience, saying "i didn't finish this story this story finished me" and "so much sleep deprivation over this" (mornmeril 2021). Some users acknowledge these types of tags as a fun way to engage with other users. For example, a user on Tumblr commented on a post detailing AO3 tagging guidelines that the post "left off some of the fun ones" including author details, giving examples like "I Was Drunk When I Wrote This" and "The Author Regrets Nothing" (https://elfwreck.tumblr.com/post/183750178884/ao3-tags-101). This communication through commentary tags introduces elements of the author's identity and experience into the user experience of reading a fan work and can subtly impact the user's perception of the resource by providing contextual information about its creator.
[5.11] Finally, commentary tags can serve as an informal method of cultural preservation on AO3. Online culture is particularly ephemeral, and online fandom practices shift, migrate, and evolve rapidly (Fiesler and Dym 2020). Commentary tags capture some abstract pieces of fandom culture like inside jokes and memes or popular characterizations for fan-favorite characters. For example, the tag "Zuko is an Awkward Turtleduck" on AO3 indicates a specific portrayal of the character Zuko in a fic and is also a common reference within the Avatar: The Last Airbender fandom. Its use on AO3 dates back to 2010, and it is still frequently applied to recently posted fics (https://archiveofourown.org/tags/Zuko%20is%20an%20Awkward%20Turtleduck/works). Tracking this tag also tracks the popularity of this fandom characterization. AO3 is a particularly useful location for this type of preservation since other popular fan platforms like Tumblr have complicated navigational and organizational functionality and have little guarantee of permanence. As De Kosnik (2016) points out, corporate-owned platforms can delete fan content at any time, and they historically have done so. AO3 is owned and operated by fans, and as long as fans are willing to maintain it, the archive will continue to exist. Commentary tags, a practice migrated over from Tumblr, are one of the many pieces of fandom culture preserved on AO3.
[5.12] Commentary tags, such as the ones included on the fan work Charting Stars On A Stained Glass Ceiling, serve purposes beyond search and discovery. They can attract new readers to a work, contextualize and qualify descriptive tags, manage reader expectations, give the reader an insider look at the writing process and a personal connection with the author, and even preserve aspects of fandom culture. In doing so, these commentary tags enhance the user experience and deepen user engagement with the fic in ways that go beyond information discovery and could translate to nonfandom spaces as well.
6. Implications for information systems
[6.1] Information scholars have discussed some ways in which expressive tagging practices exist and function on social tagging platforms. Lee and Schleyer (2012) identify purposes beyond description for tags that include users calling attention to their own resources, expressing their identity or opinions, and organizing tasks and information. Feinberg (2011a, 2011b) argues the potential benefits of incorporating authorial voice into information systems such as encouraging deeper engagement with resources. As explored in the previous section, commentary tagging on AO3 exemplifies the potential benefits of intentional implementation of expressive tagging. Fan tagging practices on AO3 demonstrate how commentary tags could enhance information discovery by drawing interest toward a fic, providing context, managing reader expectations, supporting community spaces, allowing for communication between authors and readers, and preserving elements of fan culture. These benefits could translate to other social tagging websites that allow for commentary-style tagging practices, such as LibraryThing.
[6.2] Tags allow users to gauge their interest in a resource before viewing or reading it. On AO3, a mix of descriptive and commentary tags can pique users' interest in a fan work and prompt them to read it. Adding commentary tags to other information systems could similarly point users toward resources they may not have considered otherwise. As an example, the user-generated tags applied to the LibraryThing page for the book The King of Attolia (2006) by Megan Whalen Turner include some commentary tags that could draw interest toward the book from browsing users. One such commentary tag is "reminds-me-of-rosemary-sutcliff," indicating that a user saw similarities between this book and the novels written by the English author Rosemary Sutcliff (https://www.librarything.com/work/404049). This could influence a user to read the series if they read and enjoyed novels by this author. Similarly, opinion-based commentary tags like "superior-worldbuilding" and "extra-clever-plotting" could attract readers interested in stories that emphasize those narrative elements, which descriptive tags alone cannot as easily convey.
[6.3] Commentary tags on AO3 contextualize and qualify descriptive tags on fics. This benefit could translate to information systems more broadly. Descriptive tags are generally neutral and leave much of their meaning up to interpretation. For example, the descriptive tag "romance" on the LibraryThing page for The King of Attolia indicates the presence of at least one romantic pairing in the story but provides no further context (https://www.librarything.com/work/404049). Commentary tags can emphasize or de-emphasize descriptive tags' relevance to the story. In this example, the commentary tags "subtle-romance" and "mind the age gap" qualify the descriptive tag "romance" by implying the romance is a subplot and not the main focus of the story and also warn readers that the romantic pairing includes an age gap (https://www.librarything.com/work/404049). This practice also serves to manage user expectations regarding a resource. A user may have been drawn to the book based on the descriptive tag "queens," but the commentary tag "not-enough-female-characters" warns potential readers that while female characters are present, they are not necessarily the focus of the story (https://www.librarything.com/work/404049). The inclusion of these commentary tags contextualizes descriptive tags and helps potential readers make informed decisions about the tagged book.
[6.4] Including commentary in tags can also foster community building by promoting discovery of like-minded users alongside relevant information resources. Fandom practice intentionally builds community through tag use. This is particularly evident within fan communities on Tumblr where specific tags define community involvement. Additionally, commentary tags can develop more personal relationships between users. On AO3, authors use commentary tags to invoke fandom references, like specific characterizations, that only other users in that fandom would likely recognize. This could easily translate to other social tagging websites, particularly those around media tagging like LibraryThing. On the record for The King of Attolia, some users added commentary tags with specific references to parts of the book like "I am KING!" and "I have a cunning plan" that would only be understood by other users who had read the book (https://www.librarything.com/work/404049). Users can also include commentary tags to indicate their personal interpretations of media content to draw attention from like-minded users and build upon collective perceptions of a resource.
[6.5] On AO3, authors can open a dialogue with their potential readers through commentary tagging by providing their comments on the story and their experience writing it. This communicative element deepens user engagement with the resource in ways that can translate to other social tagging systems. Feinberg (2011b) found one example of this practice in the Seattle Art Museum's user-created bibliography system. While many users in this system used tags for descriptive and organizational purposes, one user, michelem, included commentary in their bibliography that identified attributes of art pieces and invited other users to join in by phrasing them as questions. Michelem's commentary in their bibliography "inspir[ed] the reader to appreciate and engage [with] the art" by initiating an open-ended conversation with other users. Similar behavior can be found between users on LibraryThing. Users employed commentary tags on the record for The King of Attolia to either recommend the book to the others, with tags such as "worth reading again," or discourage potential readers by tagging "so-so" (https://www.librarything.com/work/404049). Such use of authorial voice in tags opens a dialogue between users and can complement existing descriptive tags.
[6.6] Commentary tags on AO3 preserve elements of fandom culture and practices, and this could translate to other social tagging platforms as well. Commentary tags capture more information than is initially evident. Even seemingly meaningless tags like "I laughed so hard at this" convey the contemporary attitudes surrounding a resource. The previous section describes the ephemerality of fan content online, and this applies to most communities on the internet as well. Tags that reference and contextualize internet memes and trends also record their use on online platforms. Even on the LibraryThing record for The King of Attolia, users referenced an internet meme in the tag "cinnamon rolls" (https://www.librarything.com/work/404049). In this way, commentary tags hold potential as informal methods of preservation online by targeting rapidly shifting data like attitudes and culture.
7. Conclusion
[7.1] From an information discovery standpoint, for fans and information professionals, commentary tags may initially appear problematic. They are deemed "unfilterable" by wranglers on AO3, viewed as "slightly" to "massively annoying" by some users, and classified as "meaningless" or "marginalia" in conventional information systems, but they serve a purpose beyond searchability (Price 2019; Gursoy, Wickett, and Feinberg 2018) (https://web.archive.org/web/20220218190133/https://fail-fandomanon.livejournal.com/31498.html?thread=143584266). Fan use of tags on AO3 provides a case for commentary-style tagging in information systems and its potential benefits. While excessive use can result in search and discovery issues, pairing some commentary tags with descriptive tags can deepen user engagement with a resource. Commentary tags draw new users to a resource, provide them with additional context, open a dialogue with other users, and potentially preserve aspects of online culture. Fan communities openly employ commentary-style tags for these purposes.
[7.2] Some social-tagging information systems like LibraryThing have already started seeing these added benefits and could improve their services through more intentional implementation. In most cases, social tagging platforms would require no additional functionality to implement commentary tags. On open-tagging platforms, users can, and likely already do, add tags in this style. It would require a culture shift of broadening the understood purpose of tagging beyond just information discovery to embrace a more communicative style. Potential future research could evaluate the presence or absence of commentary tags on other social tagging platforms and examine their use in relation to those on AO3 and other fan platforms. Instead of denouncing these tags in information systems as meaningless, exploration of multipurpose tagging systems could broaden information discovery, both within and outside of fandom, to encompass elements of discovery, creator expression, and cultural preservation.
8. Acknowledgements
[8.1] A huge thank you to Ryn and Shira for your comments and support, and to all the fans who let me include their posts and works in this article.