Tagging - You're It!

My personal conclusion about tagging is still undecided. I know for sure that it could never replace subject headings and the control and precision that comes with them. It has the potential of complementing subject headings because of its reliance on natural language - seems to me that if you somehow marry the two, you get the thesaurus you need to navigate what can be the confusing world of subject headings.

I think this passage from the Wikipedia article lays out pretty well the pitfalls of tagging -

"In a typical tagging system, there is no explicit information about the meaning or semantics of each tag, and a user can apply new tags to an item as easily as applying older tags. Hierarchical classification systems can be slow to change, and are rooted in the culture and era that created them.[10] The flexibility of tagging allows users to classify their collections of items in the ways that they find useful, but the personalized variety of terms can present challenges when searching and browsing.

When users can freely choose tags (creating a folksonomy, as opposed to selecting terms from a controlled vocabulary), the resulting metadata can include homonyms (the same tags used with different meanings) and synonyms (multiple tags for the same concept), which may lead to inappropriate connections between items and inefficient searches for information about a subject." (http://en.wikipedia.org/wiki/Tag_(metadata)

Thus, you get increased retrieval, possibly increased relevance, but you clearly sacrifice precision in the process, especially if the process is open to everyone and anyone.

An example of this would be to go onto Flickr and search for "depression glass" under the Tags Only feature (with the quotations). You get 1359 results, and one particular photographer has used that tag for just about every one of her photos, so I saw a silver plate ladle, a cross stitch table runner, and a framed print of a child praying. Other users had employed that tag for tatting lace, a picture of a 1969 Macy's flea market, and a black glass gravestone, of all things. Without the quotations, you get 339 results, some related to depression as a mental health condition, clearly not what a searcher probably wants. It was interesting to me that I got a lower retrieval rate without the quotations; the quotation search found some accounts which had used a tag combining the words into depressionglass or a tag of depression glass as a phrase, and the quotations had the system search for intact phrases. The 338 result search clearly was doing a Boolean search, requiring depression and glass to be two separate tags within a record. As expected, depression alone gave way to 20,000+ results, and glass alone yielded 810,000+ results.

This is not unlike problems we have in cataloging, where the individual cataloger decides on subject headings that may or may not match the user's notion of what a particular title is about, or where one cataloger's poorly done record is replicated a million times through copy cataloging and now hundreds of library catalogs are affected (I have just experienced the frustration with this problem while trying to create a bibliography of books on disasters and survival). So, no system is perfect.

When you have a lot of cooks in the kitchen you can arrive at a wonderful meal, or a mish-mosh. It just depends. I think tagging is definitely here to stay, and I hope that tagging will evolve into something that will allow a user to impose, intuitively, more precision at the point of search, so that each search does not yield more results than can be waded through in a reasonable amount of time.