Facebook is more like a phonebook of people you know (either wellish or by blood). Next generations of users aren't going to use it to broadcast unfiltered things simply because their parents and grandparents are on it. But that doesn't mean they won't use it. It's not 0 sum. You'd use it to notify your grandma you're graduating for example, or any non risque communication. I know, doesn't stop idiots on there, but for the most part, Snapchat and Instagram are better vehicles for expression and social validation.