Are people reading the complete article? I take the author not to be claiming that this happens because Groupon sucks. In fact, I think only the third hypothesized reason of five for the decline is actually a problem for Groupon. The fact that Groupon users may be more critical in Yelp reviews is only an indirect problem (ie. people don't want their Yelp reviews to go down), but isn't evidence of a fundamental problem with the model.<p>But the article suggests a number of very plausible reasons that have nothing to do with bad experiences. Further, as they say, until the compare these effects with any influx of customers, there's absolutely no evidence that Groupon isn't actually performing better with this metric than, say, running an ad in the paper, or getting featured on Oprah.