While the San Francisco Chronicle article on food bloggers affecting restaurants with "amateur" reviews does feature our own Sam, the rest of the article kind of gets my dander up -- take a look at it here. It makes no distinction to posters on something like Yelp vs. food bloggers who work hard to be responsible and responsive in their write ups.
I will say that the changing scrunity restaurants are getting is probably a good thing. Maybe being concerned about possibly smarmy posts or looking for trends in the comments (one example is a restaurant owner who increased portion sizes after he saw it was a big issue with reviewers) will help food businesses bring their A game to the table all the time. On the other hand, I personally have a healthy skepticism about non-food blog restaurant comments and posts on Citysearch, Yelp, etc. I read them but don't rely on them. So often they are unreliable as to the larger experience to be had.