A chat host basically leads the chat, in terms of being the one who’s in charge of starting it and ending it, and steering it along the way as necessary to keep the chat writing-related so it doesn’t get off-track into too much banter/randomness. The chats start out with everyone checking in with their writing progress for the previous week, and at the end of the chat, participants each set their writing goals for the next week.
The Thursday chats have specific topics; historically the Tuesday ones haven’t, though that’s left up to the host. (I haven’t checked in on Tuesday lately to know if Dwale’s doing a topic now or not.) The chats themselves aren’t reposted anywhere, you could always go back through the shoutbox history (the clock icon in the upper right of the shoutbox) and view them that way.
And anyone can do it, although they need to be able to commit to hosting on a reasonably long-term basis (think months, not weeks). Having to miss a week here or there because something comes up isn’t a big deal, but mostly it needs to be a time and date that you know you’re going to be able to show up on regularly.
There’s a Coffeehouse Chat info thread here that mentions some of this:
http://www.anthroaquatic.com/forum/index.php?topic=453.0
At this point, since we still have 2 scheduled chats going on per week, I’d like to keep the Saturday ones on hold for at least the rest of the summer. I also have an idea for a different weekly event, but I’ll make another thread about that when I have a bit more time.