We don't pay for 100% uptime. We pay so that we don't have to put the time into operating a service. That way we have more of our time to focus on our business problems.

If you're willing to tolerate these kinds of outages, you don't have to spend much time operating a service, either.

The problem is the time spent talking to the users.

If I own this service, it's not enough that I just reboot the service when it goes down. I'm now responsible for when it's slow, when it doesn't do what someone expects, when the user doesn't understand what the service does correctly, when someone forgets their password, etc.

"Foo as a Service" is as much (or more) about transferring the customer service responsibilities for dealing with the end users as it is for delivering the service itself.

While that's generally true, chat is pretty straightforward and it's not that hard to set up a IRC or Matrix server and direct users to download and configure a client. Besides, when Slack goes down all the time, your IT guys are going to have to deal with users complaining anyway.

> your IT guys are going to have to deal with users complaining anyway

Except that IT can say "Complain to Slack or complain to your manager that we shouldn't use Slack. Don't complain to us."

This is remarkably valuable--doubly so if your management is stupid and regards IT as a cost center instead of as something useful.

> chat is pretty straightforward and it's not that hard to set up a IRC or Matrix server and direct users to download and configure a client.

Is that true? Take Single-Sign On, for example. That's remarkably non-trivial for IRC. I'm skeptical it's any easier for Matrix/Slack/etc.

Actually it's only two nine's, which means Slack can be down for 52 minutes every year.

> 1. We purposely made our commitment to the ‘fourth 9’, viz. 99.99% uptime guarantee in contrast to the typical SLAs which tend to offer 99.90%. We believe that extra availability makes a difference: the ‘fourth 9’ is important when your team relies on Slack every day. You need Slack at least 9,999 out of every 10,000 minutes. [1]

[1]: https://get.slack.help/hc/en-us/articles/204113126-Service-L...

99.99 is four nines, not two. https://uptime.is/four-nines

Assuming the failures are deterministic across workspaces (is that true?) Slack has been down for over an hour for some workspaces, since the problem started at 10:54 AM EDT.

What is the A part of Stack's SLA?

I think you mean 4 nines.

You pay for "close" to it, but no chat app is going to have 100% uptime at scale.

A frequent use case seems to be internal chat for medium size companies. I’d wager that for a majority of the user base it doesn’t need to work ”at scale”. Hopefully, outages like this will serve as a reminder.