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.
I think it's the background-on-a-background. I see a rectangular white area behind the content and a light grey background surrounding the white area. The whole thing should be white so the pieces of the page seem like they are naturally grouped together instead of trapped and constricted together inside the little white rectangle.
If anyone is a ruby-ish person in Toronto, ON and they want to work on Hot Or Not and other similar sites, i'd encourage you to email me at jamie.wilson@avidlifemedia.com
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.