Library Applications

The library applications for Web 2.0 I enjoyed most were Shelfari and Book Mooch. I'm not much of a reader but by making a bookshelf through Shelfari I have the façade of being well-read. The books on my virtual shelf are Sustainable Living For Dummies, The Witch of Portobello, and Veronika Decides to Die. I'm actually reading all three of these books now, but that is very rare for me. Maybe the OCLS website could have an option for patrons to create a virtual bookshelf in their accounts? I like Book Mooch because it's very environmentally-friendly. On this site you can trade books with other readers, saving money and trees!
PopUrls seems like a very cool site. I love the layout, but I think I will have to explore it a bit more to figure out its applications.