Seeing this documentary on Trip Advisor reminded me of that. It shows two kinds of extremists going head to head. One one side, the reviewers who enjoy the newfound powers the web gave them. One the other, business owners who think customers should all be quieted unless they have something positive to say.
Of course these two words collide abruptly on the web, and the documentary is quite interesting and even a bit disturbing, when you understand that one of the reviewers is actually using his reviews as a way to rebuild his ego after going through a bullied childhood. He is the guy you see being so picky about things, creating a sense of usefulness through more-than-reasonable attention to details.
Catch Attack of the Trip Advisors if you can, it is running on channel 4 these days, and in VOD if you live in the UK here (YouTube preview here).