Your point about Yelp reviews is good, but I'd say that reviews from people with Groupons, Living Social deals, going on Restaurant Week, etc. are generally worthless, and I've often wished for a way to filter them out. And it's really for much the same reason that I think restaurants tend to not value those customers a lot. First, if they'll only come in with a really great deal, they're not likely to become repeat customers at full price. And it's not profitable to nurture a customer base who only buys when there is a sale (just ask JC Penney). And since they've already demonstrated themslves to be "thrifty," they're also less likely to buy extras like alcohol, dessert, etc. that make the visit profitable. There are few businesses that want to attract people who care only about price, but that's the behavior that Living Social and Groupon encourage.
Secondly, and admittedly on a much more anecdotal note, it seems that these customers are prone to acting entitled and complaining loudly about things that are non-issues compared to the regular clientele. Most people who don't like Thai food simply don't go to Thai restaurants. But there's a pretty decent Thai place near my house that tried Groupon, and got a handful of really bad Yelp reviews from people who seriously seemed to just hate Thai food. A couple of them explicitly mentioned Groupon, and the owner told me that she believes that all of those reviews were Grouponers (and the deal didn't restrict what they could buy, so they got the same food as everyone else). Their complaints had nothing to do about the specifics of the restaurant (which has almost universally good reviews). This serves no one. The diners get a meal they didn't like. The restaurant takes a ratings hit. And Yelp users see artifically low ratings for a good restaurant. If I'm looking for a Thai restaurant, I don't care what people who dislike Thai food think -- I already know they'll hate it.
Secondly, and admittedly on a much more anecdotal note, it seems that these customers are prone to acting entitled and complaining loudly about things that are non-issues compared to the regular clientele. Most people who don't like Thai food simply don't go to Thai restaurants. But there's a pretty decent Thai place near my house that tried Groupon, and got a handful of really bad Yelp reviews from people who seriously seemed to just hate Thai food. A couple of them explicitly mentioned Groupon, and the owner told me that she believes that all of those reviews were Grouponers (and the deal didn't restrict what they could buy, so they got the same food as everyone else). Their complaints had nothing to do about the specifics of the restaurant (which has almost universally good reviews). This serves no one. The diners get a meal they didn't like. The restaurant takes a ratings hit. And Yelp users see artifically low ratings for a good restaurant. If I'm looking for a Thai restaurant, I don't care what people who dislike Thai food think -- I already know they'll hate it.