You don't need real identity verification to prevent fraud, you just need mods, which already exist (Elite) if only Yelp would get their head out of their ass and make Elite mods. They need a karma system. You need karma to write reviews that count towards the rating. I generally ignore reviews by people without friends. But in the current system, AFAIK, their vote still counts and it's the same as mine (Elite).

I feel like this self regulating system could work, just like fake profiles on Facebook don't work.