I am trying to connect with a developer who uses gitter, which is something I was not at all familar with a few hours ago. I'm not willing to use Web clients or proprietary tools to connect with developers, so I had to look into what free-software clients I had access to. I didn't find a gitter client in Guix, but I learned that Gitter is connected to Matrix, and Guix does have Matrix clients.
The next mystery was how to connect to the gitter room:
Quaterion had a menu option for connecting to rooms, but I wasn't sure what room alias to use. I resolved this by hovering over the "Chat Via Matrix" button on the Web page above, and found "#punyforth_Lobby:gitter.im" which worked. I posted my issue in the room.
Screenshot of a gitter room viewed through Matrix
So anyway, now I am connected to Matrix and to gitter (via Matrix) if anybody wants to connect with me via those systems. My username is lispmacs, same as in IRC.
I've had a lot of people suggest matrix lately, mainly because it can hook to pretty much any other client, like gitter, irc, nc talk, etc. Seems like it was simple for you to set up, but looks like it gets complicated when bridging to other services.