Heh, that's *not* how to run an online chat with a guest who is supposed to respond to questions. You don't just leave the channel open and let the masses pound on their keyboards.
I ran a bunch of online chats in that vein back in '96, during the Republican and Democratic conventions that year - I was working for CNN. Did chats with Bill Frist, Rennie Davis (Chicago 7), Candace Gingrich, some chick who was on "Real World" and had gotten into politics, and Bill Press/Bob Novak from Crossfire, and the reporter who had broken the story that week about that one Clinton adviser who was banging some hooker and letting her listen in on phone convos. (Also did a big one with Magic Johnson, later in the year - boy that was a circus.)
I had the guest(s) on their own laptop, and me as moderator on my own - and I had a bunch of canned "how this chat works" text bits prepared, that I could go copy and paste into the chat every few min (to catch folks joining later). I had the channel locked down, and told folks to send ME their questions privately. I would then look over recent questions, pick a good one, and throw it out into the open, where the guest would see it, and give them time to respond. Then I'd toss another question out right after, keeping a good tempo up.