Interesting point - what if your reviews are shared between your friends? Our findings are that people can be honest in a community where they know their recommendations will mostly help their friends find great places.
If your friends are homogeneous and outgoing, you might achieve the critical mass necessary to have more than just one review on a handful of local businesses.
On Yelp, I have many local places with 0 reviews period, let alone by people I know.
Broader comment: Tying identities to reviews won't do squat. If I tell you I'm Bob Thurmond, put up a photo of an older white guy, and exercise even a modicum of identity management, who's going to be able to tell otherwise?
If I want a recommendation from my coffee aficionado friend... I'll just ask him.
We're looking to solve that problem as well -- its a darn big challenge!