While it's not labeled the same, there is a feature in place that allows for this. If they add the forum they moderate to their watch list and then turn on immediate notifications, they'll get an email with every new post.
Are you sure that's working? Because I have my Help Forum on my Watch List, and I have By default should anything added to your Watch Lists be emailed to you? enabled, but I've never gotten any emails...
I was actually gonna ask about this myself
GangsterBB.NET (Ver. 7.6.1.1) PHP Version 5.6.40 / MySQL 5.7.23-23 (was 5.6.41-84.1) / Apache 2.4.54 2007 Content Rulez Contest - Hon Mention UBB.classic 6.7.2 - RIP
For what it's worth, I've just turned on this very functionality - and I'm running 7.0.2 - and I didn't get a mail for the post I just made. Or is the software being intelligent and not telling me about my own message?