Heh. I misremembered the date--thought it was today, but looks like it was October 5. On that day, 10 years ago, I posted a link to Mastodon on Hacker News, with the title "Show HN: A new decentralized microblogging platform". That it made it to the front page ended up bringing the first 5,000 users, setting the project on the trajectory it's on today.