It may sound odd to consider that tags have a value to academic life on the Web. Understandably, tags make some librarians nervous. The ability of users to assign keywords (tags) to digital objects might signal a draining away of the authority of librarian controlled, professionally maintained, useful-for-searching classification systems.

If you're not too familiar with the phenomenon of tagging, check out the post on TechEssence for a good overview. Also look at Thirteen Tips for Effective Tagging for advice on the practice of tagging.

I don't see much reason for librarians to conceive of a rivalry between classification systems such as LC and tagging. Tags are an online phenomenon of the masses. No one is suggesting that we use tags as a system for shelving library materials. No one is suggesting that we do away with classification systems as a search option in online catalogs. And no one is suggesting that tags have the same virtues as classification systems. These two phenomena serve different purposes and are succeeding pretty well in fulfilling them on their own.

Tagging is a natural extension of the social, participatory, personalized Web. Users can set up accounts on various sites such as Flickr (for photos), Del.icio.us (for bookmarks), Library Thing (for personal reading collections) and tag what they upload or save. On sites such as Technorati, blog categories can become tags.

Tagging has both advantages and disadvantages, but the advantages are winning out by virtue of tagging's widespread use. Tags can be searched, shared and semantically associated, and can lead to a whirlwind of discovery. On many sites, they function like citations in that you can use a tag to search for something, view popular items linked to that tag, and then view other tags associated with these things to retrieve additional related things, and so on. In searcher's parlance, this is called "pearl growing."

Users are dealing with the fact that most tagging systems these days require use of a single word - resulting, needless to say, in an awkwardness and inconsistency in word combinations that can make searching a headache. Referencedesk? Reference-desk? Reference_desk? Reference? Desk? This problem, however, is not new to the Web. For example, HTML meta tags and Dublin Core labels have similar issues.

Tags can appeal to both the long tail of obscure interests as well as the mega-popular. For the former, search for something obscure that interests you on Technorati using the "in tags" search option and see what you get. (I searched for "melisma" and didn't retrieve any results. There is still room for more tagging!) On the opposite end of the spectrum, visit Flickr's Popular Tags page.

Tagging can be a good thing, in fact a very good thing, for the academic Web if its potential is realized. A few initiatives show inklings of the possibilities. PennTags, a project of the University of Pennysylvania Library, gathers tags from Web sites, databases and the online catalog. Connotea, recently added to IngentaConnect as a bookmarking site, offers tagged bookmarking for scientists and researchers. Take a look at its tag cloud to see this in action.

Here are a few ideas on how tagging can enhance the academic Web. Some are already underway, and some are wishful thinking.

1. As with the Penn Tags project, users can tag records in catalogs and databases, providing a discovery avenue for themselves as well as others.
2. On social bookmarking sites such as Del.icio.us and Connotea, librarians can create and tag lists of useful resources on individual topics. This might appeal to certain users more than the typical subject or class pages so ubiquitous on library Web sites.
3. Librarians can tag their own Web pages, tutorials and blog entries on social bookmarking sites.
4. Database providers and online publishers can allow tagging of their resources.
5. Tagging on Google Scholar, Google Book Search, Windows Academic Live, etc. can increase the usability of these somewhat chaotic sites.
6. Tagging local digital collections, open access repositories, institutional repositories, etc. can add access points for searching.

Ultimately, I see two main advantages of tagging in the academic enterprise.

For librarians, tagging can become an additional, albeit informal, resource discovery system they create that can lead students to recommended scholarly resources.

For students, tagging can become a strategy for engaging in resource discovery, organizing findings in ways that are personally useful, and whether intentionally or not, sharing their concepts with others as they engage in their own discovery process.