Personal anecdotal evidence
Of what? Of the notion that weak tie community of the online sort does constitute enough connection between people to activate the social aspects of your brain. If you're interested in more detail about the "social" aspects of the brain,Social Intelligence is a good introduction.
My anecdote is simple. I take some pride in the fact that I think I have a reasonably effective work/life balance. I'm sure approaches vary, but mine works for me. For the last several weeks, however, I've been out of balance. Work made more demands than a balanced schedule would allow. No big deal really. It happens.
But when it happens, something has to give. What gave, in this case, was the time I'd ordinarily spend in my RSS reader keeping up with the contributors there and the world that continuously unfolds therein. And I missed it.
I missed it very much. Tuesday night I plugged back in, for just an hour. I couldn't believe what I'd missed. Perhaps worse, the efforts I was expending at work would have been both higher quality and perhaps even streamlined, had I not unplugged -- lesson learned. (That and the difference between a presentation and briefing -- but that's another story.)
Stranger for me was this feeling that I missed the people. This is odd because I don't know these people in any ordinary sense, and I'm confident they don't know me in any sense at all -- with just a few exceptions.
Hmmm. I suppose we can't dismiss the possibility that I'm suffering some sort of breakdown.
In any event, I haven't checked in on anything recently contributed by Dana Boyd, but she might know if anyone has ever applied any scientific rigor to understanding the degree to which online "social" activity engages your brain physiology and how/if it compares to it's in-the-flesh counterpart. There must be something.