I don't think so. Anyone that was serious about a particular area, such as a hobby, profession, or social cause was already using forums 10 years ago. Now these people converged to the mainstream sites such as twitter, but they have always shared information on the web since it was created. My wife, for example, doesn't know a thing about computers, but is more active in forums and niche sites than I have ever been.
I know many counterexamples, particularly people who were in their 20's, 30's and older ten years ago. MySpace and Facebook was their first introduction to the social web.
I follow a beekeeping forum, and just yesterday there was a thread about some people noticing they had been on for 10+ years. These are definitely not the young hacker crowd. That predates myspace and is literally just an example that came up yesterday, I'm sure I can find older forums.
And are you really saying that before web forums, all the way back in the very beginning of the web people weren't being social on the web by sharing links through email? Remember, email is the true killer app of the internet, the web is just a nice-to-have. :)
