Web 2.0 applications have been all the rage for some time. One of the most successful applications is LibraryThing. At free for up to 200 books, $10/year, or $25 for a lifetime of cataloging, it is a great bargain. There are a lot of ways genealogists are using this tool.
The most obvious use is to catalog the books in one's personal library. With the ability to import records from hundreds of worldwide bibliographic tools, it takes only your imagination to find a library catalog that might have that resource in your hand so that you don't have to catalog it manually. For example, I had a publication that I had picked up at a genealogical conference that was published in Ireland. I found a library in Ireland that had that title in their collection and used their record. I will admit that there are titles that I have that are pretty unique. I have had to enter these manually. Since I'm a cataloger by profession, that doesn't bother me. However, I know that I tend to be pickier about my cataloging than others are. Instead of subject headings, one can use tags to identify the books. Many people also tag locations of their books such as "shelf 16" or "box 22".
LibraryThing also gives one the ability to add reviews of items. If we genealogists used these reviews to their full potential, we could really keep up with strengths and weaknesses of various titles. In my experience, reviews are more honest on LibraryThing than at Amazon.com.
One of my favorite features of LibraryThing is the ability to find similar libraries. I have found many fellow genealogists using these. I add them to my friends, to my "interesting libraries," or to my "private watch list." That way I receive notifications of additions they make to their libraries. I'm able to find some titles of interest this way and often order them or add them to my wish list.
I don't know of many genealogists who use LibraryThing for their wish list, but I do know there are a lot of users who do and use the tag "wish list" for the items that aren't in their library. LibraryThing really would prefer that folks only use LibraryThing for things they own or have read.
Many of us use it for things we have read but do not own. I typically use the "NIL" (not in library) tag that many other LibraryThing users for these items and then add a location code for them. I have tags for books borrowed from friends and for books borrowed from libraries. They probably mean nothing to most people, but they mean something to me.
Then we have the "thinking outside the box" type of LibraryThing user. One of my genealogist friends has taken the various journals in his library and entered each article as a title. He uses the tags he has devised to easily locate articles in his personal collection. It's kind of like a PERSI index that is limited in scope to the journals in his own possession. The more and more I see his entries, the more and more I'm tempted to do the same thing for some of mine. I tend to forget about those lists of insolvents and transcribed censuses of schoolchildren that appeared in various issues of journals, but they are tools in my library that I could be using more often if I included them in my LibraryThing catalog and tagged them.
LibraryThing also has groups, but most of the genealogy groups are not very active.
Do you use LibraryThing? Do you have any special way of using it?