It's also free software and easy to set up so I encourage everybody to check it out.
I like WeeChat as a client, it's fast and lean and works inside the tmux session that pretty governs my digital life both private and professionally. Alas, it's not always accessible. Getting Putty to reliably work with tmuxed ncurses apps is a nightmare for example, imho.
Glowing Bear solves this brilliantly. It looks great, you get features like inline display of media and is easily secured with certificates from Let's Encrypt.
Thank you, devs. This'll make my "newly discovered FOSS projects of the year" list for sure.
By contrast, if you want to switch off Slack, can you still talk to people who stay on Slack, or do you have to get them to switch too?
I like IRC over Slack for the same reason I like email over Slack: I can just use my client with the interface I like, and the network takes care of getting my message to someone using a different interface, that they like. It doesn't require we compromise on a shared, fixed interface, a la Slack.