Twenty-five years ago, I co-founded Wikipedia, arguably the most important encyclopedia in human history. On Monday, I was indefinitely banned from the site. The story of what happened to me is, in many ways, the story of our censorious times, in which independent thinking is seen as a threat rather than a virtue, and punished as such.

Let me back up.

In early 2000, the internet was a very different place than it is today. It was much freer—tools of censorship weren’t nearly as advanced—but it was also harder to use, and finding information took much longer. The need to make the internet more user-friendly was clear to those of us who spent a lot of time online. We needed a free, fair storehouse of knowledge: an encyclopedia built by, and open to, the public.

It was exhilarating to build Wikipedia at that time. Never before had a global, volunteer-written encyclopedia been shown to work. We applied the principles of open-source software to knowledge: All users would have a seat at the table, everyone would edit each others’ work, and the results would be free for all.