> they worry about bad things happening, but mostly they just worry that their kid has a whole private life that they don't know anything about and they're not part of it.

i had a whole other life my parents knew nothing about, and this was way before unsocial media. the fact that we're willing to call "friends" online a social life is yet another example of modern times. so again, having "secret" lives from parents isn't new to being online. it's teens looking to push the boundaries, explore, and just do things different from the parental units. nothing about "kids today" is really different. Boomers had that damn rock-n-roll and hippies as an example. It's more of the same in a different shape.