"Chat" mode means real-time
interaction: you type a message and receive immediate replies.
There are several Internet
tools for chat:
All of these have the disadvantage
that they are (or can be) "open", with lots of guaranteed-objectionable
messages. If you choose eGroups for your mailing list, use their
chat feature also, because then the participants are "known quantities",
and you, as moderator, have the ability to bounce them off the service
if you do not approve of their activities.
IRC (Internet Relay Chat)
AOL Instant Messenger
Chat programs may offer some
or all of the following:
One-on-one or group chats.
Audio/video (with appropriate
Instant drawing ("whiteboard")