zeitgeist
We have a handful of members after day 1. I should point out that one of the most interesting features of the group is the page containing the group zeitgeist.
ArchiText
LibraryThing continues to impress. Book groups can now be set up on the site, so as you might expect I’ve leapt in and started one for the architecturally interested. The paint is barely dry on the walls but come and help me build it into something useful: www.librarything.com/groups/architext