Fatdoor launched its service yesterday at Where 2007. The service consists in helping you get to know your neighbours, and build communities.
When you register, you enter your address and Fatdoor displays your neighbours: the ones they collected from the US White Pages and, increasingly, the ones who registered on Fatdoor.
From that point, you can enrich your profil, or the profil of your closest neighbours, like in a wiki. Of course, if you bad-mouth about your neighbours, you will soon be banned from Fatdoor's community.
You can also create groups of interest, based on hobbies, political interests, etc. And soon, at least that's what Fatdoor is betting on, you'll know you neighbours and share your interests.
Business model ? Nope. But one day, local advertising :-)