I am afraid, if FB decided to chase Yelp, they would significantly reduce it. All they need to add are check-in stats and start rating with user profiles who visited a place. It'd almost work better than the subjective long Yelp reviews: just from looking at the public view of people's profiles who visited, and the star ratings they gave, I could figure out what kind of crowd likes/dislikes a certain place. Also, the amount of check-ins would be massive, if I was able to see all check-ins, even out of my network.