All of my friends had AIM as well. But that was not true of people even five years older. All of those things that you pointed out existed, but they were not the kind of assumption that Facebook is now. Web-based social sites starting with Friendster, then MySpace, and now with Facebook opened up online interactions to most people in the Western world, as opposed to the geeks, or family members of geeks, or the young, or people with special interests.
The point is not that people were not social on the web before. The point is that many, many more people are social on the web now, and that it's becoming an assumption of society. And from what I have witnessed, this is clearly a result of social networking sites.
You're basically making a non-refutable argument since anyone who responds to you here is going to be an HN commenter whose experience is disqualified by your premises.
At least provide some data to back up your claims.
The point is not that people were not social on the web before. The point is that many, many more people are social on the web now, and that it's becoming an assumption of society. And from what I have witnessed, this is clearly a result of social networking sites.