What is Mastodon, and why are so many users leaving Twitter to join it?

All the different instances on Mastodon can communicate to each other — that is, what users in a certain instance are posting is accessible to users in a different instance.

Here is an analogy to explain the technology better: When a user first creates an account on Mastodon, they will have to choose a server or instance they want to join — similar to how, when they create an email account, they choose between Gmail, Hotmail, Yahoo etc. that generates their profile address.

No matter where a user initially creates their email account, they can still send mails to users on other email platforms. Now, imagine that happening over a single platform, with the different email services being different servers, or instances.

What are these servers, or instances?

Users or organisations can even start their own servers. Otherwise, there’s a list of servers which focus on specific locations or topics of interest. So, if a user chooses to join Mastodon via a clime justice server, their username would be [name]@climatejustice.social.

Similarly, if someone joins Mastodon social, their username would be [name]@mastodon.social. Both these users can still communicate with each other and see posts on their servers.

The admin of each server can decide the content moderation guidelines for that particular server.

What does it mean that Mastodon is “open source”?

It essentially means that anyone can download, modify and install Mastodon on their own server. The developers of the platform don’t own the copyright.

However, if someone creates a platform using Mastodon’s code, they will have to acknowledge the source of the code. Former President of the United States Donald Trump’s social media platform, Truth Social, initially launched with Mastodon code and passed it off as if it were original software, until Mastodon called it out.

How does content moderation on Mastodon work?

Since Mastodon is a collection of thousands of different servers, there is not a singular content moderation strategy for the entire platform. Content moderation is done by admins of each server who can set their own rules — this means that a kind of speech allowed on one server may not be allowed on a different one.

Server admins can also make their domain block-lists public, as Mastodon founder Eugen Rochko has for mastodon.social.

Users can also migrate to other instances on Mastodon. Here’s an example to illustrate that: assume a user joined a Mastodon instance on, say, climate change. Now, down the line, if a certain user, or group of users start posting content that is hateful, illegal or extremist, other users on the instance can migrate to a different instance and cut ties with the previous one.

Migrating users can choose to block the previous instance, in which case the new one they join will not be able to communicate with it. If that happens on a large scale, it would mean that eventually, people who do not align with some of the extremist views shared by certain users on an instance will leave it, leaving the accounts to talk to their own shrinking band of followers and users on their isolated server.

Why the migration to Mastodon?

Since Musk’s takeover, Mastodon has garnered more than half a million users. The exodus is largely the result of confusion and concern resulting from the flip-flops that have come to define Musk’s short reign over Twitter.

Musk initially said that he was a “free speech absolutist” but post his takeover, the platform started suspending accounts of users who had changed their profile names to Musk’s along with his profile picture.

He later said that users impersonating others would be immediately banned by the platform until they specified “parody” in their account — however, some users who did that were also banned by Twitter.

After allowing users to essentially buy verification marks for their profile with an $8 subscription of Twitter Blue, Musk said that prominent personalities like politicians will be given an additional tag of “official” on their profiles.

However, within hours of launching the “official” tag, he scrapped it saying that it was “another way of creating a two-class system”. He later tweeted that in the coming months, Twitter will do a lot of “dumb things”.