I think that in the past "teens" didn't have a separate culture. Communities were tight (compared to the bare resemblances of community we have now), and younger humans were more focused on becoming a part of the community's culture.

I think what you may be describing is how interacting on the Internet has allowed some immature adults to use the lack of connection in communication (eye contact, body language, voice inflections, etc) to behave like children. I think this is a product of recent culture, which, I hope, changes direction.