Wondering exactly who some of these people are who you befriended on your Facebook page?

Well, oddly enough, that could be a good combination these days.

Burger King this week launched an application called the Whopper Sacrifice. Taking its name from the fast food company's well-known burger, the Whopper Sacrifice rewards Facebook users who delete 10 of their online friends with a coupon for a free Whopper burger. The application can be downloaded from either Facebook or from the Whopper Sacrifice site.

"What would you do for a free Whopper?" the site asks hungry visitors. "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."

Burger King, which last year released the BK Polarizer widget that gauged people's political views, is trying to ride Facebook's popularity wave with its primary customers -- 18-to-34-year-olds who chow down on fast food burgers.

What better way to play with the notion of what really is an online friend than to judge their worth compared to ... a hamburger? And Burger King is showing no mercy, though some good humor, by having the application send a message to the deleted friend to tell him that this person valued a Whopper more than their friendship. The app also acts as a counter, reminding the user how many more friends need to be evicted before they get that free Whopper.

The news of Burger King's funky campaign comes just as Facebook announced that it has hit a milestone of 150 million users. Facebook CEO Mark Zuckerberg noted in his blog yesterday that while the social networking site has 150 million users, nearly half of them use the network on a daily basis.