Long answer: My colleagues don't want to so I use it mostly for forums. Some programming languages have chat channels and I have heard that for open source dev it is still somewhat common but I suspect it is declining. It's a pity because I think Slack is stupid. Slack does not have the transparency of IRC and frankly the fact that you can share files and use fonts and indents are not selling points for me.
EDIT: Slack is stupid for me. To each their own I guess?
EDIT2: Just to make it clear, judging from other answers a lot of programmers use IRC every day. But not all of my colleagues are programmers. Some fall in the chasm between "data science" and programming and for such people IRC is unfortunately unfamiliar.
Indeed, you're still paying for electricity to run a server somewhere of course. ZNC, Quassel, The Lounge, WeeChat if you want to do it yourself. IRCCloud if you want to pay someone to do it for you.
We used bots to do that, but in todays world it's so easy to just stay logged in all the time, just leave a screen or tmux session running as a background process on a server
Would people pay for for a cloud service that bridged some of the gaps between Slack and IRC. Like notifications and offline message retention. Or would you just use Slack in those cases?
Some would consider that a feature, you only see the activity of the channels you've joined (but you can search for others at any time and you can preview messages in them before joining).
switching the channels is slow & non-intuitive
isn't "/join #channel-name" the same way you switch channels in IRC?
Most IRC clients allow you to quickly switch to frequently viewed channels via shortcuts (even irssi, a terminal client, does that). With Slack it is a clunky Ctrl-K and a first few letters of the channel name that may or may not lead to what you really want.
Yep, must say I miss the Escape-sequences for changing channels. Works fine via wee-slack though but unfortunately you need permission to join via wee-slack since it requires an API-key.
?? Slack has shortcuts for both of these. Cmd+0,1,2,3 to switch between orgs, opt+up/down to switch between channels. And also, as you mentioned, cmd+k for search-switching
I know Slack does support shortcuts, but search-switching is inferior to a direct shortcut. Let's say that you frequently use channels a and b in the org A and a channel c in the org B (this mode of operation is common). How do you get to a, b or c without even looking at the screen?
Long answer: My colleagues don't want to so I use it mostly for forums. Some programming languages have chat channels and I have heard that for open source dev it is still somewhat common but I suspect it is declining. It's a pity because I think Slack is stupid. Slack does not have the transparency of IRC and frankly the fact that you can share files and use fonts and indents are not selling points for me.
EDIT: Slack is stupid for me. To each their own I guess?
EDIT2: Just to make it clear, judging from other answers a lot of programmers use IRC every day. But not all of my colleagues are programmers. Some fall in the chasm between "data science" and programming and for such people IRC is unfortunately unfamiliar.