When we moved here I signed us up for Angie's List. Because I have never had to find reliable plumbers and tree men and whatnot. I didn't even know who to take my newly acquired dry cleaning to. I also use Yelp, Urbanspoon, Google, and word of mouth. To date I have saved thousands, mostly on a plumbing deal that could have gone really bad.
While I do get what you are saying I also know that I don't give equal weight to all the ratings. You can sort of tell the nutters form the actual customers. What I look for is repeat behavior. I also check the BBB and frankly, Consumer Reports if I can. I've always done this, my grandfather started me on it back when he was alive and used to get Consumer Reports magazine. I like it- the whole feedback situation. It allows me to tell others when I have a great experience and it allows others to tell me what they experiences without me getting the "filtered by the business" version that testimonials sometimes are.
I also will get on Twitter and shame a business or applaud them. I watch what my Twitter friends are doing and I often try places because they did. There's a little local place around the corner called Miso. I'd have never tried it on my own because it was a noodle bar and I hate miso. But after hearing others rave about the veggie dishes guess where my new go to place is? Miso will make it not because Grant, the owner, is a fabulous marketer- he's not, but because his food is so excellent everybody tells everyone they know to go there.
On the other hand.....I recently spent some Christmas money on some macaroons. French macaroons are expensive as fuck. I thought I picked well. They arrived and I found some had been dipped in chocolate. You don't fucking do that to macaroons! Dammit. Especially if you didn't tell me. You may have well shit on my macaroons. I wasn't stabby yet (just sad) though until I saw the sweetly written on the packing slip request for a review on Amazon. Oh she got a review all right. Macaroon ruining bitch. So there are times it may backfire.