On the one hand, you could file this under, Duh. On the other hand, quantifiable! Super cool.
I particularly liked that Luca says this:
"For Seattle alone, the website had over 60,000 restaurant reviews covering 70% of all operational restaurants as of 2009. By comparison, the Seattle Times has reviewed roughly 5% of operational Seattle restaurants."
Reviews by unreliable amateurs of the restaurant you are thinking about going to are _far superior_ to reviews by trained experts of restaurants you are never likely to set eyes on, much less enter and eat at. Same principle for lots of other things, too; it's no wonder newspapers have so many problems.