How were people communicating before FB? When you have that answer, you realize how futile is to depend your whole life & friends' + family's on FB.
Before Facebook and its ilk, part of the definition of "former friends" and "extended family" was that they are categorized as people you rarely communicate with, or not at all.
Before Facebook, you didn't need Facebook to ignore your former friend or to rarely talk to your second cousin on the other side of the continent. Today, you still don't need Facebook for this.