I inadvertently joined Goodreads this week :)
A couple of weeks ago I posted about joining LibraryThing (read post here). LibraryThing is an online cataloguing tool for your books. I signed up, and started adding books to "my library". I got a cool widget for my blog (look at the right sidebar), and if you click on any of the book covers a popup will give you the catalogue record for the book and my rating and review if I have written one. I've been pretty happy using LibraryThing except for one thing - LibraryThing is billed as a social networking site, but I'm not feeling very social about it. There is an option for adding friends, and you can visit other members' profiles to leave comments, but it's not really working for me.
Now here's a blog that's got it all for the discerning, book-reading gal!