While I've seen the filtered reviews issue and think the claims are somewhat true, my bigger problem is that yelp does nothing for reviewer quality.
So many times, I've seen blatantly false and misleading information tacked on to someone's reviews. The site allows both the microcomments "Food, okay. Waitresses, hot." and the long, trailing rants about how the steak tasted rotten. This is a problem, and not one easily fixed. Being an "Elite Reviewer" just means you give out more idiotic reviews than the rest.
Yelp is a joke to anyone who really cares about food.