I have been on CH for over 10 years now but since moving away from a major metropolitan area to a much smaller town (albeit still one with a population over 1M) with less of a CH presence about 6 years ago, my perusal of UrbanSpoon and Yelp reviews has steadily increased to assist in augmenting my local restaurant knowledge. I read CH more now for other boards than my local one but read Yelp and US only for local reviews.
Now, I have never been one to give much credence to a solo glowing review or slam of a restaurant either way, but it seems to be that there are a LOT more disgruntled one time "reviewers" out to slam a restaurant based on a single dining experience than previously over the last few years. It almost seems that the individual is so affronted by the single (worst) experience that it becomes his/her mission in life to slam said place on the innerwebs (sometimes with the exact same review on Yelp and US). Is it just me or am I just getting more cantankerous in my old(er) age? And what really jerks my chain is when the "reviewer" starts off with "I have been here x number of and formerly loved it" or "I eat all over the world" or even "I'm a foodie (ugh)" yet the person has never written any other reviews, good or bad, on the site(s). This drives me bonkers.
Alternately, there are a few “reviewers” that provide glowing reviews of a place which come off as shilling. I can deal with that. What really gets my goat is some reviewers only review the same place over and over and over, making that one place sound like it’s the best thing since sliced bread. And those tend to be for places that basically suck.