I need Yelp!

Ok, so Yelp is supposed to be the next big thing on the web from a Paypal co-founder. It's basically a social networking system where you can ask your friends for help on stuff like a good restaurant or this or that. It handles the emailing and that sorta stuff for you, but I'm not sure if it's actually useful. How is it better than actually emailing yourself? Maybe I should spend the time to try it.