"You like your friends, but you love the Whopper".

Burger King is running a promotion in the States that encourages Facebook users to delete mates in return for flame-broiled beef.

The "Whopper Sacrifice" campaign and Facebook app challenges users of the social networking site to "put [their] fairweather web friendships to the test".

The Whopper Sacrifice application can be installed on a user's profile, then using the app, if ten friends are deleted, Burger King will send the deleter a voucher for a Whopper.

According to the promo site, it appears to be working with 50,265 Facebook friends deleted State-side so far.