@flancian @edsu @sam @Matt_Noyes @mako @ntnsndr @dazinism
On another different line of thought/software, I had really great experiences with Zulip (https://zulip.com/).
What makes it great from my POV is the serious thread model. It helps to know what is happening, keep context, focus on what matters for you (including notificacions), mark as done, etc.
It is not federated, but it is Free Software and we can self-host it.
Anyone else tried it? Do we want to make a test?