Facebook Inc.’s ads have begun to appear on social gaming provider Zynga Inc.’s web site, marking the first time the social network’s ads have appeared on a site outside Facebook.

Consumers who are logged on to Facebook who visit Zynga.com will see Facebook ads—both Sponsored Stories, which are the posts and other actions by brand and consumers on the social network that are promoted by a brand, and Marketplace ads, which are display ads on the right-hand side of Facebook.com. The ads appear on the right sidebar of the page, a location required based on an advertising arrangement filed with the U.S. Securities and Exchange Commission by Facebook and Zynga in February. The ads use the same targeting as ads on Facebook.com. 

“The Facebook ads you see on Zynga are the same ads you see on Facebook.com,” Facebook posted on Facebook.com. The social network notes that consumers will only see Sponsored Stories about activities that have been shared with them, that they can remove ads that don’t interest them by clicking an X box and that it doesn’t’ sell identifying information to advertisers.

Analysts have long speculated that Facebook could leverage the large amount of data that consumers share on the social network in an ad network. By experimenting with placing ads on a site other than Facebook, the social network is fueling speculation that such an ad network could be in the works.

Zynga could not be reached for immediate comment.