It’s not just a fact of life, but also a policy on Facebook. While many trivial actions do prompt Facebook to post an alert to all your friends — adding a photo, changing your relationship status, using Fandango to buy tickets to “Paul Blart: Mall Cop” — striking someone off your list simply is not one of them.

The campaign, which boasted of ending 234,000 friendships, is history now — Burger King chose to end it rather than tweak it to fit Facebook’s policy — but the same can hardly be said of the emerging anxiety it tapped. As social networking becomes ubiquitous, people with an otherwise steady grip on social etiquette find themselves flummoxed by questions about “unfriending” people: how to do it, when to do it and how to get away with it quietly.