It used to be that waiters would be especially aware and courteous around those who could make or break a restaurant with a review (either written or verbal/viral). Managers would point out these wheelers-and-dealers, saying so-and-so writes for the Globe or so-and-so is a very important person.
But these days, with yelp, citysearch, and heck, even blogs like this one, everyone's a critic. No waiter can think, "Oh, these 20-somethings obviously have no influence so I'm not going to pay much attention to them." These days, the writing of semi-anonymous yet often inciteful critics on the internet really have an interesting effect... a bad review, even if it comes from an unknown source, is still a bad review.
As if the restaurant business didn't have enough trouble! Two points for the guest, -1 for the restaurant . . .