Just yesterday I posted a story where Nomura Equities Research issued a buy for Facebook. Their reasoning:

[…] But Facebook’s ace in the hole is what Nowak and his colleagues are betting on: The company’s deep treasure trove of user data […]

How would they use this data? My only guess was that they would create their own external ad network for use by sites outside of Facebook.com. It appears my guess was spot on.

According to Inside Facebook, it appears Facebook is already placing ads on Zynga.com. Facebook even notes the external ads in this Help Center entry.