I've been hacking at a basic version of ad-free, subscription based group messaging, coordination, event planning, etc - check it out! https://get.thread-app.com/
I really liked the idea of Google+ Circles when they first came out. It allowed me to organize people I interacted with into a focused group; work, Linux, TF2, etc. If I wanted to talk about AWS, I could switch my brain into that mode and just post things about a single topic. It was really nice.