For a hobbyist: a review is a way to know how a provider works, how good she is at her job, and for their safety, there's no better way to know she isn't LE or a robber. Repeated good reviews also give a provider a great reputation, and it gives her clients a consistent report of how she conducts herself.
For a provider: it means she isn't viewed as a risk in her community anymore. It gives her an edge in advertising as a "safe, respected, local powerhouse". A good reputation for providing a steady, sensual, and fun experience can also allow her to up her hourly rate.
The downsides: A review can be faked by a service. The provider pays an online service to pump out positive reviews (to improve her standing ) and to get her name out there (it's not free, but it's advertising).
A review can also be faked by LE.
A review can be extremely inaccurate, for example: a client who forgets to mention that you used condoms, or who says you were able to deep throat him but you have the most sensitive gag-reflex in the world.
A review can be used to hurt a provider's career for example: an ex who publishes a rob report, or says you have an STI (in an attempt to harm your business and ruin your reputation.)
A review can be used against you in a court of law as well. It's an account of your time together with your client. There is no "we just snuggled and watched Netflix" when the review says "and we had a tumble after the shower too."
Publishing reviews is a great way to keep a balance in a community of members, but reviews also give guys a way to brag about their conquests, and once they have enough conquests, they also get a reputation.
"Senior members", "trusted advisers", "escort aficionados"... They are respected by their peers, but occasionally (not every board, not every site, and not every time), they let this reputation go to their heads. They start asking for free sessions for good reviews. They trade their approval for free sex.
Honestly though, there is no power in a good review. After your first two reviews, you can become a P411 verified provider, and you will never need another review ever.
I no longer ask for reviews, and I let my clients know that I prefer not to have any record of our time together.
Rub girls: you cannot get a better review than one that makes your DON'Ts clear for your future clients.
"She won't do FS so don't ask." "No mutual touch found here, but the HE was ASTOUNDING!" "She's a safety girl so condoms for everything, but she really knows how to make it feel good, even with the raincoat."
Menus are a big NO now-a-days, but your clients can say whatever they want to because it's either slander or heresay.
Another thing about reviews: when you have 4 or 5 come out within a week of each other, it's really telling about how many clients you take... Higher volume girls are often higher risk (just because of their exposure to sexual partners. There's no judgement from me, it's just something to know about reviews.)