julcnx
(julcnx)
3
Alright, it’s not quite what I was envisioning. 
I was thinking that Discourse might have a feature similar to Facebook groups where you can use “@everyone” to notify all members of a category.
If that’s not an option, I was thinking to compile programmatically or manually a list of participants in the Community and contributors in OSM, and then send emails manually from my own account.
Would that be considered spam?