#19 sites from Web2.0 awards

I had fun with the classified winner, Craig's list. My son uses it in VA and I wanted to see how it works. For fun Cocktail Builder shows you what you can make with linited ingredients. Yelp tells you what real people think about restaurants, services,etc. in your city. I didn't find anything library related except the library thing which would be helpful to keep track of good reads.