Is anybody else here using LibraryThing? I found out about it recently when bradhicksposted about it, and have just started using it myself. Essentially, it's a book-cataloging web application with social networking features. You can enter the books in your collection (automatically looking up details on a number of sites such as Amazon or the Library of Congress) by name, title, or ISBN. Aside from being able to search, sort, and tag your own library (using some of the best bulk-operations tools I've seen in a web app), you can rate books, post reviews, see who else shares books in your library, etc. I haven't yet taken the time to fill in up to the free limit of up to 200 books, or do more than glance at the social features, but I do hope to get more of my books logged, and start getting more out of the site, over time. Anyway, my own library listing is here.