A couple of the award-winning Web 2.0 sites I explored were Wufoo and Mango. I can see Wufoo being very useful for creating library websites. You could make forms available online for patron requests, reconsideration requests, mailing lists, or surveys, all without having to write any HTML code, as the website points out. For non-library-related reasons I found Mango interesting because I am a long-term sub candidate for teaching Russian at my school and I need to brush up on the grammar and vocab. But I think it would be cool to have a subscription to Mango available on library computers to help bolster the foreign language curriculum.
I had heard of Ning before but I didn't know that you could create your very own social circle. It would be ideal for a book club or any after-school club. Just for fun I joined "Hair Metal Generation".