Have you ever played Tag? It’s a game where someone is "It" and has to chase down and tag (touch) another player to transfer It to one of them, then run away before the new It tags them back. There are many variations -- some of which require It to tag all of the other players before they can turn It over to the last one tagged. No special equipment is required, just room to run around and at least four or five friends.
Social tagging is "the process by which many users add metadata the form of keywords to shared content," (Wikipedia). Have you ever tagged a photo on Facebook? As you begin typing a name, you are presented with a list from among your Friends matching that spelling. You are encouraged to use these names, predefined by your friends, to link to your Friends. Only then will they have your picture added to their Photos of Me. This is a form of controlled vocabulary. Tagging is a feature specific to Web 2.0 and is of particular interest to librarians.
The Library of Congress Subject Headings (LCSH) are used to categorize books according to subject matter. The LCSH is controlled vocabulary that has been used by librarians to help patrons find books in the catalog. This was especially helpful in the days of the card catalog when you had to know the correct term (and spelling) used to describe your subject. For example, if you were looking for books on battered women, child abuse, or domestic violence, you would need to know to look in the drawer for Family Violence. The big red books would help you find the right vocabulary to use in your search. You also had to know the filing rules (i.e., Mc is interfiled with Mac) -- and how to alphabetize.
When the computerized OPAC (Online Public Access Catalog) came along we could do keyword searching but, unless your keyword is in the title, you often still need to know the term (and spelling) used by the LCSH to describe your subject in order to find what you are looking for. Now some OPACs are opening up to user participation – social tagging.
The worry for librarians is that to replace controlled vocabulary (no matter how imperfect it is) with uncontrolled social tagging in the library catalog will be chaos! What is to keep spelling and punctuation in check? What prevents [the wrong] people from tagging their [incorrect] opinions or pranksters from using inappropriate terms?
Nevertheless, the Darling Library is testing outWorldCat Local which is an interface to our catalog that allows you (HIU library patrons) to tag records with terms that you find useful and add reviews. What we like best about it is that it searches journal articles as well as books. But, our current version of WorldCat Local only searches a limited collection of electronic journal articles. (For an annual subscription price, we can upgrade to have it search all of our and articles along with books, videos, CDs, and more in one search.) Check it out, and let us know what you think. Be sure to select Hope International University from the dropdown menu unless you want to search for books in Libraries Worldwide.