It's just crazy to many of us that a reinvented IRC is suddenly "not dead" and in vogue again. Not unbelievable, just kind of surprising how quickly text chat on a channel format was cloned, rebranded, and valued for billions.
I never understood what Slack did better than Hipchat, and not in a nerd sense of "well Dropbox could be replaced with rsync, a VPS and some shell scripts, m'glayven". I never understood how they killed Hipchat, IRC, or anything else. I don't know if they have a strategy to deal with things like Microsoft Teams that is very attractive to companies who already work with Office 365/Active Directory or if they can reall…
Stay up? I was at a company that was on Hipchat, and we really liked it, but the amount of downtime got to be semi-unbearable. We switched to Slack and it had much better uptime.