Wired: Facebook Rolls Out Highly Targeted Viral Ad System

The real kicker is the third component. It essentially collects the data from the first two components (keeping user info anonymous, of course) and provides it to a given business to assist in its targeted advertising objectives. For instance, a user who goes to Coke’s page and interacts with or installs its viral app (“Sprite Sips”) can pretty much expect to become a shill — inserting all sorts of branding messages and endorsements into friends’ News Feeds.
…
We suspect that Facebook Ads means more app spam … lots and lots of product-pushing app spam.

All kinds of potentially creepy privacy issues there. I’ve already seen instances where third-party apps were able to display otherwise privacy-controlled information, so it can only get worse.