Telephone numbers and home addresses change all the time, and communicating the change of this information is a hard problem that requires effort that most peop

Telephone numbers and home addresses change all the time, and communicating the change of this information is a hard problem that requires effort that most people won't put forth. On the other hand, Facebook accounts just stay the same. It doesn't matter where they live or what Nth phone they happen to have, they've always got a Facebook account. I don't know everyone else's use cases for Facebook, but in my case it's just a way to be able to keep in contact with people I'd otherwise be losing contact with.