• by Mark Walsh  @markfwal, January 15, 2009

It looks like the Whopper Sacrifice promotion has hit a speed bump.

The Burger King application released last week that lets Facebook users "sacrifice" 10 friends in return for a coupon for a free Whopper became an instant hit.

But it appears the popular app has run afoul of Facebook privacy rules, resulting in a key feature being shut down. Specifically, Facebook has stopped the app from generating notifications informing deleted friends (and their friends) that they have "been sacrificed for a Whopper."

Friend removals on Facebook normally take place without a notification being sent to the deleted friend.

"We encourage creativity from developers and companies using Facebook Platform, but we also must ensure that applications follow users' expectations of privacy," said Facebook in a statement released late Wednesday. "After extensive discussions with the developer, we have not disabled the application but have placed some restrictions on the application to assure that users' expectations of privacy are maintained."

Crispin Porter + Bogusky and Refresh Partners, the agencies that developed the Whopper Sacrifice app, could not be reached for comment Wednesday. While generating controversy, the notification feature of the Whopper Sacrifice app was also viewed as key to its viral success. In a post about the matter Wednesday, the blog Inside Facebook said the app was used by 82,000 people to delete over 230,000 friendships on Facebook in the last week.