Back in December 2009, Google's failed to acquire Yelp for $500M. According to TechCrunch, "While there is no price per share or valuation designated on the form, reports have held the desired valuation at between $1 billion to $2 billion."
Just the other day the company ran a blog post boasting that the website hosts 22 million reviews. Yelp reminding everyone that it's "not just a restaurant review site," in that "shopping is now on parity with restaurants as the most reviewed business category on Yelp." Unsurprisingly, the company plans on trading under the symbol "YELP."