The Bulletin Board software keeps track of who commented on which email and puts these threads into a graphical diagram. Perhaps the biggest drawback is that the visitors have to visit a Website to see the latest Bulletin Board discussions. Participants can only keep up with the discussion if they regularly visit the Bulletin Board site. In Chat Rooms usually only 2-6 people can type back in forth at the same time in a virtual discussion. The biggest problem with Chat Rooms is they have to be synchronous.
People have to be sitting at their computers typing at the same time.
Not very likely, unless that topic is very compelling. Recently many of the vertical portals have been hosting celebrity chats to draw new traffic to their sites. Bulletin Boards and Email Discussion Lists are asynchronous and have an enormous advantage over Chat Rooms. They concentrate on a specific topic. Most newsletters are one-way communication, but some newsletters can create a sense of community with an interactive flavor.