Social media stocks have been struggling. The biggest exception to the routs faced by Facebook (FB), Groupon (GRPN) and Zynga (ZNGA) is Yelp (YELP), where millions of people go to review local businesses — and sound off about rude waiters. It has bucked the trend since going public last March.

Yet it’s tough to see what makes it fundamentally different.

Tags: local, yelp