“I found there were quite a few people on my list that I’d never even spoken to, much less been close friends with,” he said by telephone.

Mr. Schiff, 25, said he experienced only the slightest guilt at eliminating those people. While he didn’t feel the need to write to them individually to explain things, he did use his personal blog to address them en masse.

“Let’s be honest here, questionable Facebook friend,” he wrote. “We’ve been keeping you around all this time because we’d just feel bad if you ever found out that you got the ax. It’s just, well, up until now nobody offered us a Whopper in exchange for your feelings.”

This was just the sort of sentiment that Burger King and its advertising agency, Crispin Porter & Bogusky, were aiming to evoke when they set up the campaign. Burger King decided that it would do the talking for this article rather than its agency and delegated the task to Brian Gies, a vice president of marketing who said he was not a member of Facebook and therefore had not participated in the “Whopper Sacrifice.”

Mr. Gies explained the marketing team’s thinking about Facebook. “It seemed to us that it quickly evolved from quality of friends to quantity,” he said, “which was interesting to us because it felt like the virtual definition of a friend became something different than the friends that you’d want to hang out with.”

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From there, Mr. Gies said, the team started wondering: “Do you really want to have all these people knowing what you’re up to and what you’re interested in? We wanted to be part of that conversation and part of that solution, and ‘Whopper Sacrifice’ was born.”