This. The product description is extremely appealing to me - it tackles exactly what I find to be most wrong with current social network software. If I could, I would begin using it immediately and would probably get 60-80 people in my network to do the same and try it with me.

If this product gets any traction, it seems like a near certainty that Facebook will launch a "Circles" UI for their groups feature, very quickly, no?

I understand why Google is taking it slow, but if the idea sounds like old news by the time Google lets me invite people, I suspect they're going to seriously compromise their odds of user adoption.