San Francisco’s Yelp Inc. has so far been a typical Silicon Valley success story. Founded in 2004 by members of the so-called PayPal Mafia, the company has made its investors and employees a lot of money.

Co-founders Jeremy Stoppelman and Russel Simmons and board member Max Levchin were all senior engineers at PayPal Inc., in the early 2000s, and along with other early employees and investors in the payments company have been big players in the Bay Area’s startup scene.