(Answer by Thibault)
I never intended to make a popular chess server. I just happened to start one, at a time when it was needed. Out of sheer luck.
Back then I was learning programming and enthusiastically trying out web technologies. I was contributing to many open source projects, and creating lots of them. Mostly garbage which I was abandoning after a few days.
Lichess was one of these throwaway learning projects. I was trying out realtime communications between browsers, and after a solid 5 seconds of thinking of a dummy project to experiment with, I decided to make a chess board.
So I hacked it up quickly, to learn about XHR long polling. Then I put it online, and then I moved on to the next toy project as usual.
However someone started using it, to my surprise. So I added a chat to communicate with that person. I got scolded by them because the board allowed illegal moves. Fine. I fixed that. And then the next bug, and then they must have invited some friends, because suddenly there was a few players online. So I kept adding bugs and fixing them.
You know how it ended. It turned out, there was a real need for a free software chess server. One that would treat players as people and not cattle. A chess server without ads, trackers and paywalls.
So the online chess community jumped on the occasion to build it with me.
I was extremely fortunate to be the person who was at the right place at the right time. Lichess would have happened without me, with another founder and another name. It may also have been a lot better then, so I apologize just in case.
My point is that I did not really create it, the chess community did. All they needed was an initial spark, to light the fire, and they picked mine. Thank you!
Also see the online lichess FAQ