Eugen Rochko was annoyed with Twitter. The company had made a series of changes that he thought eroded the value of the service: limiting how big third-party applications could grow, for example, and implementing an algorithm-driven timeline that made Twitter feel uncomfortably similar to Facebook. Most people in Rochko’s situation fired off an angry tweet or two and moved on. Rochko set about rebuilding Twitter from scratch.

Mastodon, a distributed, open-source version of Twitter, is almost identical to the platform it’s based on, but with key differences: posts can run 500 characters rather than 140, and users can make individual posts private. Rochko launched Mastadon with little fanfare six months ago. Then last week, Twitter rolled out an update that changed the way it displays replies; many longtime users complained that the redesign is confusing — in a piece on Motherboard, Sarah Jeong asked, “Why does Twitter hate itself so much?” Overnight, Mastodon added users by the thousands.

Just in the past 48 hours, the network has grown by 73 percent, to 41,703 users, according to the public counter on Mastodon’s about page. Those users have collectively authored nearly 1 million posts despite heavy server loads that have made basic functions unavailable for hours at a time. On Tuesday, Rochko shut down new sign-ups “until quality of service can be assured for existing users.” User interest is largely rooted in Mastodon’s alternative view of its service: one designed not first and foremost as a business, but as a public trust.

“I brought all my friends to Twitter back in the day,” says Rochko, 24. “I kept promoting it to everybody I knew. I really loved the service. But it continuously made decisions that I didn’t like. So in the end I decided that maybe Twitter itself is not the way to go forward.”

Rochko is not the first person to attempt building a better version of Twitter. In July 2012, a developer named Dalton Caldwell announced App.net, a crowdfunded Twitter clone that promised to be mostly free but charged users for certain features. Despite raising $500,000 from Twitter refugees, the app failed to grow, and it entered “maintenance mode” in 2014 before finally shutting down in January.

“Maybe Twitter itself is not the way to go forward.”

One of App.net’s users had been Rochko, who was drawn to it for the same reasons that would eventually lead him to build Mastodon. He says he has tried to learn from some of App.net’s mistakes, including a focus on becoming “a realtime cloud API company” and not a more straightforward microblogging service. (Its flagship app was also never very good, Rochko says.)

Last year, after Twitter began moving away from a purely chronological feed, Rochko began building the back end for what would become Mastodon. Instead of building a unified service, Rochko envisioned something more like email, or RSS: a distributed system that lets you send public messages to anyone who follows you on the service. Anyone can create a server and host their own instance of Mastodon, and Mastodon works in the background to connect them.

Rochko named the service after a popular metal band that he enjoys. A designer friend created its logo, a cuddly mastodon. In October, he announced the service with a post on Hacker News. There would be an open API allowing any developer to build a Mastodon app to their liking. (So far, there are at least three for Android, and three for iOS.) And there would be no advertising.

Mastodon acquired around 24,000 users in its first six months. Then came the new Twitter replies, and suddenly hundreds of people were joining Mastodon every hour.

Y'all need to get on that https://t.co/IJr3sLaj8H shizz. This place is done and it's like 2008 over there. — Fuego (@FuegoJaguar) April 2, 2017

Eventually we won't be here, here being Twitter. May not be here https://t.co/zQN44EkXK2 but it will be somewhere. — Gabriella Coleman (@BiellaColeman) April 4, 2017

Eventually we won't be here, here being Twitter. May not be here https://t.co/zQN44EkXK2 but it will be somewhere. — Gabriella Coleman (@BiellaColeman) April 4, 2017

To fund the project, Rochko set up a Patreon account, which is currently paying him about $1,000 a month. (Monthly hosting costs for Mastodon are currently around $100.) “I’m not doing this to get rich,” he says. “I’m doing this because I think it’s right. I only want to be able to pay my rent and insurance.”

So far, the Patreon is covering his expenses. But if the service continues to grow, that could change. In the meantime, he’s encouraging users to set up their own instances of Mastodon, which will spread the costs out among the user base.

Social networks as pop-up restaurants

In recent years, social networks like Mastodon have resembled pop-up restaurants. They serve items you can mostly find elsewhere, but they have a novelty to them — as well as a sense that you should go to them now, before they inevitably disappear. Diaspora, a privacy-focused Facebook clone that launched in 2010, is an early example. Ello followed, and then Peach.

There’s no reason to assume this Mastodon will avoid extinction. But in the meantime, it’s one more example of the internet unbundling Twitter into its core parts, and then serving them elsewhere. If Twitter can’t get the job done, a growing number of developers will do it themselves.