The mockups look great.

Gut reaction is that you are clearly inspired by Facebook, but there's only so many ways to peel this particular orange. I'd consider a primary color change as a quick and painless way to distance the two; I think it's the blue that's keying me to Facebook the most. There's an argument about whether that's fair, that they psychologically own social blue in my mind, but better to differentiate (in my mind).