Yay for LibraryThing! I already have an account there - I discovered the site about a month before Learning 2.0 started. (So far I've only catalogued a few of my manga series and some books I recently bought, though) Nifty place - for those of us who are absent-minded, it's also a good way to keep track of what you have. (When you have as many books as I do, it's harder to keep track of them all than you'd think!)
Check out my LibraryThing account here, if you're interested. (I'm also in the group "Librarians who LibraryThing")