"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.


Chat programs may offer some or all of the following: