I don't know if mass mailing is possible in the sense you ask, or whether people would want it; one of the reasons we went to a forum was to get away from the mass amount of emails when we were a Yahoo Group.
You can however set your own notification preferences for when a post as been replied to, and for when a new topic has been started in a board. See
https://rpug.pdc.ca/index.php/topic,60.0.htmlTo get notified when a new topic has been started in the RailPro Software Updates board, you would simply go to the board (it's index page, not to any individual thread in the board) and click the notify button. You would then get an email when someone posted a new topic to that board.
- Tim