Email validation before reviews go live should also help.
Ofcourse emails are like IP's, a dime a dozen, but it's one more loop.
ya i thinking about that, all the ideas i came come-up with just make the user jump though hops to get the review online...
I wanted it to be Super easy to write a review, this is why i based it on ip so the user wouldn't even have to login.
I'm now toying with the idea of requiring a btc address & amount paid, as a proof of payment... needless to say this idea has problems aswell.and / or
the more reviews they post the higher their reputation, the more impact their rating will have on the listings score.