met these guys today. you can vote/contribute on menu items and restaurants. you get recommendations, accordingly.

Quoted: Find menus and user reviews for restaurants all over the US, including the best of Chicago, San Francisco, Seattle and more. Rate what you ate and get daily recommendations.

Good points in this article. I strongly agree with the basic premise.

Quoted: Before Facebook added the feature sets it has today, it was simply a more complete student directory. Facebook did not create a community where one never existed before; rather they provided an important information and communication service to a pre-existing offline community.