So looking at the bottom of the screen, looks like this forum runs on the popular vbulletin software. So hitting the google I found out that $400 and some server storage leasing can get anyone up an running should they choose to make a forum that is in another interest- other than audio.
But what I found may help AA, should you choose to employ the capabilities listed in the two links below, they are how to guides to getting your forum software to perform as I have described above.
vB Mail Reply - vBulletin.org Forum
Email Integration (New threads/replies by email) - vBulletin.org Forum
Hope that helps.