I've had a LibraryThing account since January 1, 2006, but I haven't used it much since I originally entered in my library items. For me, there is a less of a draw to LibraryThing than to other Web 2.0 technologies.
I did re-explore the site, and like looking at the suggestions and especially the unsuggestions. Very clever.
I might use it more for the suggestions than anything else. Gives good ideas for Christmas gifts.