First hints of a Facebook ad network: Sponsored Stories appear on

Zynga’s off-Facebook games platform now displays Facebook ads and Sponsored Stories, as part of what could be the beginnings of a Facebook ad network across the web.

According to the Facebook Help Center, “When you connect with Facebook on, you’ll see personalized ads and sponsored stories. The Facebook ads you see on Zynga are the same ads you see on”

Those ads appear in the sidebar, which is where we’ve previously seen Zynga serve ads via Google AdSense. The site still runs Google ad services, as seen with the banner at the bottom of the screenshot below.

Last year, Facebook told us it had agreed to work with Zynga to provide ads on their properties beyond Facebook, though at the time it was unknown what the “Zynga Platform” would be. Facebook is sharing a percentage of ad revenue with Zynga, but those percentages have been redacted from regulatory filings available here.

Both Sponsored Stories and traditional Facebook ads — those with headlines and body copy — appear on Zynga maintains the right to designate a limited number competing developers whose ads will be prevented from appearing on the site. The exact number has been redacted from SEC filings. We’ve reached out to both companies for more details.

[Update 6/22/12 9:52 a.m. PT – Facebook provided the following statement, “We have had a close relationship with Zynga for a number of years and we think we can deliver value to Zynga and to the people playing their games by showing the same ads that they see on Facebook. We will not be showing ads on other sites at this time.”]