Aggressive and creative marketing campaign by Burger King.

What would you do for a free Whopper? Now is the time to put your fair-weather Web friendships to the test. Install Whopper Sacrifice on your Facebook profile, and we’ll reward you with a free flame-broiled Whopper when you sacrifice 10 of your friends.

InsideFacebook reports that in one week, the app was used by 82,000 people to delete over 230,000 friendships on Facebook. Then Facebook placed some restrictions on the application and Burger King decided to conclude their campaign. In fact, Burger King got what it wanted: attention! In few days!
Creative use of social networking marketing!!!