Yelp is not perfect, and it's well known that they take a fee to "promote positive reviews". It's still a great service, even if it's not perfect. For the consumer it's pretty damn accurate if you know how to use it. It may be a big problem for businesses though.

I moved to a new city by myself and yelp is very helpful. Looking for a decent barber? Yelp is godsend. Want to go to an interesting little fast food place run by a small family and want to know what the diarrhea probability is? Yelp is great. Want to go out to a bar or nightclub and want to know what kind of people go there and what the general atmosphere is, and whether you need girls in your party to even get in? Just look at yelp.

I always take it with a grain of salt, and usually also look at google reviews, and if it's something that matters at least do a quick google search. I'm usually more interested in what the reviews say, and what kind of people are doing it rather than the actual star rating. If a nightclub has a review:

1/5: We were a group of 37 dudes and they didn't let us in. So pretentious.

Then I consider that a positive. Or if a clothes shop has something like:

2/5: Very poor selection of kid's clothes.

3/5: The clothes seems decent, but very poor size selection. Almost nothing comes in XL/XXL (/XS).

Then I ignore that as it doesn't mean anything for me. Or if I see 2 reviews:

5/5: Just came home. Great service, Marie really understood what my teenage daughter needed and connected with her.

5/5: Bought some jeans and shirts a year ago. Great quality, they retain their size well and handle being put in the dryer without issues. They also have great fit [reviewer image makes it clear what that means].

Then I take very different things from those.