I agree with you that there's an introvert/extravert dimension to how people screen information, but I find your anecdotal examples interesting. I have no problem with working around noise and picking out interesting details from it (when I was growing up the TV was on almost 24-7). That's different from deliberately trying to drink from the fire hose that is the Internet every day without making some hard decisions on what you will read, what you *might* read, at least sometimes, and what you won't read because life is too damn short.
Re: Out there in the social web...