Jeremy Stoppelman, co-founder and CEO of business-recommendation site Yelp, has joined the board of advisors for event-management site Eventbrite. He has also invested an unspecified amount in the company, according to a press release from Eventbrite. Stoppelman will serve as a strategic advisor, contributing his experience in local market development and social media.

Eventbrite, which allows eventholders to create and manage ticketing online, has focused much of its growth strategy on social media. It will be interesting to see how Stoppelman’s input affects this. Stoppelman was criticized by some for not implementing Facebook Connect on Yelp fast enough. “We have gotten Jeremy involved because he’s been a strong startup operator and has built a very impressive consumer site,” said Eventbrite CEO Kevin Hartz. “Jeremy is the leader in developing local markets. Our events are really local in nature and geographically bound,” said Hartz.

Stoppelman joins an impressive list of investors and advisors, including YouTube co-founder Jawed Karim, Yammer founder and CEO David Sacks, Roelof Botha of Sequoia Capital and, most recently, former CEO of Ticketmaster Sean Moriarity.

Stoppelman co-founded Yelp in July 2004 with former colleague and friend Russel Simmons. As VP of Engineering at PayPal, he was part of the PayPal Mafia, and he and Hartz have known each other for a number of years. Yelp has over 30 million unique visitors per month and over 10 million reviews. Eventbrite had 4.6M unique visitors in March, which is up substantially from the last quarter and amounts to 20% monthly compounded growth over the last few months.