Foursquare just signed a deal with Zagat.  If you find yourself running around with a smartphone in hand and don’t know what Foursquare is, you should take a look.

I think this could be the model that pushes participant-based reviews on the map, perhaps even adding elements of crowdsourcing that will revolutionize the way these places do business.  I could  easily see a tool like this combining with Opentable to deliver easy reservations and queuing.