What it does
Each mail group, is a community. I can post questions for certain communities. For example if I want to know about a new task I haven't done before or ask about how to get new equipment I can ask the communities that deal with this things.
I can see all posts from the communities I'm in. Answering questions and being active results in a higher score for your user. A higher score makes a difference when others view your questions in their feed.
This system is built to keep the knowledge of the community, a new guy can come in and look at the existing posts.
How I built it
C# for backend, elastic as a DB and Angular2 for the client.