Amused to read slack is down today, now that we've moved all of our team chat to #matrix.
For the moment we're on the matrix.org home server. Most of my team is non-technical, and getting them to move was enough of an ordeal that I didn't want to complicate it further.
Plus, I really don't have the emotional bandwidth or time to admin an instance.
It's something I may improve upon later though.
Are you self-hosting matrix or using a hosed instance somewhere?