I am experimenting with several different types of "forum subscription" programs. Please do not subscribe at this time, as I may be swapping software to get a combination that works effectively. Right now, the "subscriptions" module is active and seems to work to send email from the site to the user, but cannot accept incoming email. The "notifications" module does something similar, but hooks into the 'web mail' application which does process incoming email, so I may be switching over to that. If I do, any existing subscriptions will be lost.