Let's say I care about "HAM radios".
1. I join a group chat
2. I discover it has a FORUM too and is not just a chat
3. Then, I discover: 
- it has shared docs (that I open/use from the same app)
- the people in that group are hanging out in Nests every wednesday (that I open/use from the same app)
- I can see the podcasts, movies, recipes, ... these people valued (and open/use all these form the same app)
- some forum posts are simultaneously posted in other groups and I meet a bunch new folks that care about a related subject
- ...