Like other social applications, Facebook wants to know how you’re connected to people. So it asks: “How do you know this person?” and presents these choices:

The choice I usually want — “Through the Web” — isn’t available. One friend coerced “Met randomly” by adding “The web as a conversation engine” — but that’s an unsatisfactory workaround. There was nothing random about how we met. Given our shared interests and our online expression of them, it was inevitable that we would come into contact.

“Through the Web” should be a first-class answer for “How do you know this person?”