This is the application I've been waiting for. I'm entering books fast and furious over here. LibraryThing lets you catalog your books online - and offers tags (similar to Flickr if you use that).
The reason I was so excited was that I attempted to start a Blogger Book Exchange months ago, but I could never get around the fact that no one really had the time or energy to find out if someone else had a book they wanted to read. Problem solved.
If you're interested in joining a blogger book exchange, send me an e-mail at firstname.lastname@example.org. Participants will catalog the books they have available at LibraryThing.
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