Companies and politicians joined up. Twitter users put Mastodon usernames in their handles and trumpeted their migration. The new traffic knocked many Mastodon instances, or servers, offline. In less than two months, Mastodon’s monthly active users climbed from 380,000 to more than 2.5 million. But not everyone stuck around. Mastodon’s active monthly user count dropped to 1.4 million by late January. It now has nearly half a million fewer total registered users than at the start of the year. Many newcomers have complained that Mastodon is hard to use. Some have returned to the devilish bird they knew: Twitter. After a decade of Big Tech dominating social media, the idea of a small, alternative, and open source platform like Mastodon growing into a truly mainstream challenger was alluring to some. The decentralized platform operates very differently from services like Facebook, Instagram, and Twitter and demands volunteers take on the job of sustaining and moderating servers. That’s because Mastodon is part of the Fediverse, a network of servers running interoperable open source software. Thanks to dedicated admins, many instances survived the flood of sign-ups and came back stronger. But Mastodon never was, and never will be, Twitter. For some, that’s what makes Mastodon valuable. To others, it’s a barrier. But the Twitter migration showed that Mastodon can adapt—and quickly. “The biggest lesson of what happened is that Mastodon and the rest of the Fediverse can scale. This was a big question,” says Robert Gehl, a professor of communication and media studies at York University in Canada. He has studied Mastodon and says it’s enjoyed peaks of interest followed by slumps before. But that pattern can still add momentum. “Each time, a percentage of the wave sticks,” Gehl says. “You get people converting to it.” During Mastodon’s Musk bump, admins worked hard to get servers swamped by new users back online. They crowdfunded money to pay for increased hosting bills and updated their policies on content moderation. Schilders has recruited content moderators and has funding from donations in the bank to cover monthly server costs. But he says running the server now comes with added pressure. “You’re kind of a public person suddenly,” he says. He plans to separate his personal account from mastodon.world so he can post more freely without being connected to his admin work. Part of Mastodon’s appeal is that users have more power to block content they see than on conventional social networks. Server admins make rules for their own instances, and they can boot users who post hate speech, porn, and spam or troll other users. People can block entire servers. But the decentralized nature of Mastodon makes each instance its own network, placing legal responsibility on the people running it. Admins must adhere to laws governing internet service providers wherever their servers can be accessed. In the US, these include the Digital Millennium Copyright Act, which puts the onus on platforms to register themselves and take down copyrighted material, and the Children’s Online Privacy Protection Rule, which covers the handling of children’s data. In Europe, there’s the GDPR privacy law and the new Digital Services Act. The legal burden on Mastodon server admins could soon increase. The US Supreme Court will consider cases that center on Section 230 of the Communications Decency Act. The provision has allowed tech companies to flourish by absolving them of responsibility for much of what their users post on their platforms. If the court were to rule in a way that altered, weakened, or eliminated the piece of law, tech platforms and smaller entities like Mastodon admins could be on the hook. “Someone running a Mastodon instance could have dramatically more liability than they did,” says Corey Silverstein, an attorney who specializes in internet law. “It’s a huge issue.” Mastodon was just one of several platforms that garnered new attention as some Twitter users looked for alternatives. There’s also Post.news, Hive Social, and Spill. Casey Fiesler, an associate professor of information science at the University of Colorado Boulder, says many new social platforms experience fleeting popularity, spurred by a catalyst like the Twitter saga. Some disappear, but others gradually grow into larger networks. “They’re very difficult to get off the ground because what makes social media work is that’s where your friends are,” Fiesler says. “This is one of the reasons why platform migrations tend to happen more gradually. As more people you know join a platform, you’re more likely to join.” Eugen Rochko, Mastodon’s founder, did not respond to an email asking about the platform’s growth and the shrinking number of active users. For some, the end of the surge brings welcome relief. Rodti MacLeary’s instance, mas.to, had 67,000 active users in mid-December. By February, that number fell to 40,000. That’s still far more than before the Twitter takeover, but it’s manageable. The server bill costs about £1,000 a month (about $1,200), but enough people have donated to cover it, MacLeary says. Mastodon isn’t the same as before—there are more mainstream voices mixed in with the counterculture. But in the calm following the mayhem of last fall, admins can go back to enjoying what they liked about social media that’s not underpinned by ravenous ad businesses. “I loved Mastodon for fun. For a little while, Mastodon became work. I came quite close to burnout at the end of last year,” MacLeary says. “The numbers are down after the surge, but they’re steady. The service is paying for itself. We’ve got help with moderation. It’s back to being Mastodon for fun again.”
