This is a pretty junk article. A bunch of hype-making charts and the lack of acknowledgement that Fog Creek was already fairly mature by the time Trello came out. Trello came out 3 years after StackOverflow.
This is a low quality, very poorly edited and researched piece of borderline content spam.
Joel (& Michael) at Fog Creek are so interesting.
So many well known things came from them.
StackOverflow
Trello
Glitch
Fogbugz
Copilot (not Microsoft’s, though there’s so irony since Joel was an early Microsoft developer)
And more
Calling Trello "bootstrapped" feels a little disingenuous. It came out of Fog Creek Software, who had all the necessary people on payroll already. As far as I understand it was a side-project in an otherwise profitable and long-running company, that eventually got spun out with dedicated resources. When people think of "bootstrapped" startups, I think it's most natural to think of a team working for little to nothing, needing to become "ramen profitable" ASAP, and not having the safety net of a stable job, free food in the office, legal/marketing/HR and other support services, etc.
"Bootstrapped" from a super-cushy Manhattan office building, heh.