I think Notion (my employer) https://notion.so/product made it popular. However .so gave us a lot of trouble over the years, so I wouldn’t recommend.

Out of interest: what sort of troubles has it given? (if you're able to say)

- Corporate firewalls don’t like people visiting .so Somalia URLs. Wouldn’t have this problem with .com. We had to fight hard for domain reputation.

- Back in the day communication between us, our registrar, a middleman registrar in Germany, and SomaliNIC wasn’t too good. We weren’t notified of a takedown report and got DNS blocked by a bunch of ISPs offline for 8 hours. Even figuring out what happened on that one was baffling.

My domain uses an Afghanistan (.af) domain. They actually froze new registrations after the Kabul takeover.

I find the name 'plane' itself curious. As an upcoming product you make yourself quite hard to find in search engines (though "plane issue tracker" gives plane.so as first result in DDG).

I'm guessing it's a combination of 1) it was available, and 2) why not?

If wonder if it has something to do with shared libraries

Maybe because so is the 5th of a scale, and this has 5/8ths of the features of Jira?

For potentially confused people out there: some countries/musical traditions use a do-re-mi-fa-so-la-ti(si) scale, rather than do-re-mi-fa-sol-la-si or a-b-c-d-e-f-g.

This has the interesting side effect that the word solfege (sol-fa) makes little sense.

https://en.m.wikipedia.org/wiki/Solf%C3%A8ge#Note_names

not a bad find of an extension for a common english word. More common than notion!

= "source open"? :-)

Short for software