1. Yelp is no Apple (iPhone/iPod/iTunes; probably the best designed/marketed/developed products in 50 years. I detest the Apple approach, but I respect their success and understanding of their market).
2. Google's first social network (Orkut) launched before Facebook, but Facebook's approach was more appealing to US consumers. But we don't yet know what's going to happen with Google+. However, Facebook is no Apple either.
3. Zagat is focused on a narrower market than Yelp.

Hopefully, Yelp will continue to develop. They have a lot of value as is. However, I wouldn't want Google to suddenly enhance one of the competitors in my space. It may be that this aquisition will actually help Yelp; we don't know what Google is planning yet.

He didn't say the food was horrible, he just said he wanted to trash it anonymously online.

A successful restaurant owner does not volunteer for these "makeover" shows. If you have customers, the last thing you want is a TV crew taking up space. If your place is packed, advertising won't help. Although many of the owners have claimed the show manufactured drama, a lot of what they show would hard to create just for the camera -- unless of course it was there already. How many restaurant owners are likely to admit the findings are accurate? In the cases where the TV chef sends in a cleaning crew to address years of unsanitary kitchen conditions, it's hard to believe they brought in years of grease buildup.

I understand there are some restaurant owners who think their only problem is marketing, so free TV publicity is all they think they need. But I know of some great restaurants that are always packed. Their success is pretty much self-sustaining (even with zero advertising) as long as customer satisfaction is high. Sooner or later something happens to break the cycle and a downward spiral begins. Very rarely is a restaurant failing due to a sudden lack of advertising.