If you're not familiar, "Yelp is an online urban city guide that helps people find cool places to eat, shop, drink, relax and play, based on the informed opinions of a vibrant and active community of locals in the know. Yelp is the fun and easy way to find, review and talk about what's great — and not so great — in your world." (From the Yelp FAQ, because...yeah, I cheated.)
The link is below, and I'll also add it to the Link page.