Libel would be he thing you'd sue them for. But that's just not going to happen.
Ylp is a tool that people use. EVERYONE wants their voice to be heard,
especially if they were having a bad day... er, I mean, if they had a bad experience, and Ylp is an open platform for that.
I like to think that people are able to read the negative reviews and take them with a grain of salt.
I mean, you can certainly tell when someone is just having anger problems.
As far as buying a subscription or whatever... I've seen a few places I know do it; places with horrible (warranted) reviews, and places that are just opening.
It gives them an ability to respond directly to the reviews, for all to see.
As far as it actually being a scam, I don't know of anyone who has actually removed negative remarks.
Maybe the scam is that they say you can, but you can't?
I don't really know what my point is and I feel like I'm rambling so I'm going to stop.
It's as real as facebook et al. More reason to hire someone to do social media for you.
See? It creates jobs! Or just get some friends to bomb it with positive reviews.