The tone of the site is a little too business-ish. I can't pinpoint how, but (colors aside) it has the form of a business product like basecamp.
Take a good look at http://www.hotornot.com/ . I don't have the design chops to explain why, but that site comes across as less serious. If you can find more fun consumer sites that have been successful you should be able to identify some common design techniques.