This might be true in many places, but it strikes me as a particularly aggravating problem in Manhattan. In my family, you were supposed to be judicious and chary with restaurant recommendations, most especially with small Chinese places, not only because you selfishly hope they're not over-run, but because an inundation of customers often ends badly as the overall quality often takes a nosedive.
And this would seem to be a particular danger in NYC, because not only do we have a lot of foodies, but we're always flooded by tourists.
The immediate reason for my fuming is that while I've noticed the line for Prosperity Dumplings grow longer, and I seethe when I see it mentioned in print, most recently the line was the longest I've ever seen it. And just as I was turning away in exasperation, I heard someone say that it had gotten 2000(!) recommendations online.
So, while I love that we come to share here, I kind of hope that when we make discoveries Chowhounds don't share them promiscuously with Yelp and every other places, as if there's a need to brag. Okay, now you can all yell at me for sounding elitist. But it's really the same in other aspects of life - you don't want your charming vacation village to become a crude tourist trap, you don't want your scholarly seminar crowded with ignoramuses. You know what I mean.