On Wednesday morning, thefor three hours, throwing many far-flung employees into disarray.
Thankfully, another quick-messaging service, Twitter, was still up, and users could turn to it to complain, commiserate and joke about the Slack communication apocalypse, which lasted from 9:30 to 12:30 ET, prime work hours.
Use the phone? Email? Walk over and speak to a co-worker? What is this fresh hell?
Some pointed out that there are more than a few other ways to get work done. "With Slack down, I can only communicate by phone, text, email, Facebook, Twitter, Skype, GroupMe, Instagram and Snapchat," David French wrote. "Now I know how my grandparents did business."
Users compared the world without Slack with everything from the apocalyptic environment of the 2007 Will Smith film I Am Legend to Milhouse of The Simpsons sadly throwing a Frisbee to himself.
Some wondered what was going on at Slack headquarters. Wrote one user, "#Slack's been down for a while and it occurred to me. It's probably taking a long time for a whole bunch of people to work together on a fix, because Slack is down."
Slack maintained a page about the outage on its website while the service was down, posting a message every half-hour until the service returned.
In an email to CNET after the service returned, the company wasn't specific as to what brought it down.
"As you know, we were experiencing connectivity issues, but are happy to report that workspaces should be able to connect again, as we've isolated the problem," a Slack said. "We are so sorry for any inconvenience."
Slack was back up at about 12:35 p.m. ET. And just as there were jokes about the outage, there were jokes about its return.
First published, June 27, 9:47 a.m. PT.
Update, June 27 at 10:25 a.m. PT: Adds comment from Slack.