multi-threaded participation yes, but even more so, total focus and an extremely detailed and fine-tuned tailoring of your participation to your actual interests. other people make you listen to them, here you can easily get the information YOU find relevant. you can scan and skim without being a jackass. you get what you want quickly, most of the time.
and yes, the fact that many introverts are better developed writers than speakers. speaking is something you do with your body in a way that is in the moment. specific inflection, hands, posture, body language, eye contact, etc. writing is about putting the words on the page and letting them sit there forever, read me if you dare.