Unless if you’re really in the know about nascent platforms, you probably didn’t know what Mastodon was until Elon Musk bought Twitter and renamed it X. In the initial aftermath of the acquisition, as users fretted over what direction Twitter would take, millions of users hopped over to Mastodon, a fellow microblogging site. As time went on, users would also try out Bluesky, or Instagram’s Threads app — but because Mastodon was founded in 2016, it had years to develop its own identity as more than just an alternate Twitter. What is Mastodon? Mastodon was founded in 2016 by German software developer Eugen Rochko. Unlike Twitter, Facebook, Reddit or any other popular social media site, Mastodon is a nonprofit, meaning that, ideally, its goal is to benefit the public, rather than shareholders. Mastodon might look like a Twitter clone at first glance, but the underlying system behind the microblogging platform is far more complex. The service is decentralized (no, not in a blockchain way), describing itself as a “federated network which operates in a similar way to email.” When you first create your account, you choose a server — similar to how you choose to open an email account on Gmail, Hotmail, Yahoo or wherever — which generates your profile’s address. So, for example, if you sign up for Mastodon via the climate justice server, then your address will be @[your username]@climatejustice.social. But no matter which server you sign up with, you will be able to communicate with users from any other server, just like how Gmail users email Hotmail users and vice versa. However, some servers might have blocked other servers (perhaps if it’s an unsavory group), which would mean you can’t communicate with anyone from the blocked server. The Mastodon lingo Mastodon users generally refer to individual communities as “instances” or servers. These Mastodon servers can be run by individuals, groups or organizations that each have their own set of rules regarding how users can sign up, as well as their own moderation policies. Some servers let anyone join, while others are invite-only or require approval by an admin. For example, a server for professional scientists asks applicants to include a link to their research to demonstrate that they are, indeed, professionals. Choosing which server to register your account with might seem stressful, but it’s possible to move your account later, so don’t worry. Plus, you can follow people regardless of which server they’re on. You may also hear Mastodon described as part of the “Fediverse,” or an interconnected web of various social media services. You know how having a Twitter account doesn’t mean you can use that account on Instagram? Through the Fediverse, your single Mastodon account also grants you access to other decentralized social networks, if that interests you. Techcrunch event San Francisco | October 13-15, 2026 You may ocassionally see Mastodon’s equivalent of tweets being referred to as “toots,” but this is fading out of favor (since it’s kind of silly!). Many people are just calling them “posts” these days, but “toot” is often found referenced in older third-party clients. Mastodon supports a number of Twitter conventions like replies, retweets, favorites, bookmarks and hashtags. For a while, Mastodon made an intentional choice not to make a quote tweet-like feature, since it can encourage dogpiling criticism, but the platform relented and rolled out that feature in 2025. In addition, Mastodon lists work slightly differently from Twitter as you can only add people to a list if you’re already following them. And Direct messages on Mastodon are just @username posts, not private messages coming to a DM inbox — just remember to change the visibility settings if you want that message to stay between the two of you. Image Credits: Fediverse (opens in a new window)Image Credits:Fediverse (opens in a new window) What does it mean that Mastodon is open source? Anyone can download, modify and install Mastodon on their own server — plus, the developers of the platform don’t own the copyright. That doesn’t mean that you can grab Mastodon’s code without acknowledging the source, though. Former President Donald Trump’s social media platform, Truth Social, initially launched with Mastodon code and passed it off as if it were original software. Mastodon did not take kindly to that. How do you create a Mastodon account? When you arrive on the Mastodon website, you can click a button called “create account,” which directs you to a page listing servers to choose from. You can filter these by various factors, like region, language, topic, sign-up speed and more. There, find a server that piques your interest and join — if it’s a server that requires you to be approved, you might need to wait a bit. From there, you can start finding people to follow, regardless of whether they’re registered via y