[29athrowaway]

Slack has many competitors. You can replace it.

Does MS Office have real competitors? Google Docs is very casual compared to MS Office. LibreOffice needs a lot of work.

My money was on Corel Office for Linux (with solid products like Wordperfect and Quattro Pro), but Microsoft bought a large share of Corel and it was mysteriously discontinued.

[IshKebab]

Slack has competitors but none of them are as good. At least none of the free ones - I've tried them all. Zulip is closest but it has a weird threading model (it's more like Usenet).

It's quite surprising given how relatively simple it is.