dating back to 2003, I've been subscribed to several forums by email. This has been an advantage especially for long-lived topics such as sdk / plug-in development related, e.g. those pre 2008 lost in the switch from webex to jive. Email also gives me an easier way to watch for new entries (especially in my low volume topics) and track already read messages.
Unfortunately the current system merged various sub-forums into "topic" tags that - even applied correctly rather than with shotgun approach - are not available for email rules. I have switched to filter by plain text keywords, but occasionally come across missed messages.
Therefor I suggest to add the post's associated topic tags to the email. To me custom mime headers such as "x-adobeforum: indesign" and "x-adobeforum-topic: sdk scripting server" would be ideal as these can already get addressed by email rules. Could you eventually add such headers?
While the equivalent information is already available from the contents, a user ID similar to the "User123 just posted in a community" would also be welcome.
IMO, forum email is flaky and although they've taken steps to improve it, it still falls short of everyone's expectations. I don't use it. I disabled email from my forum account settings and never looked back.
It's easier for me to use the web forum's Notifications feature (bell icon) to see who has replied lately. If there is something I'm interested in following, I add it to My Follows folder.
Nancy O'Shea, Adobe Product User & Community Professional Alt-Web Design & Publishing ~ Web : Print : Graphics : Media