Online Communities, Identity, and Association

Mastodon is a social networking software (like Frendica) that allows admins to run individual network instances for users. Think of Twitter, but people’s accounts exist on a bunch of different servers instead of just one (replicated) datacenter. The individual servers then talk to each other, so that can follow and chat with

In many ways, Mastodon is literally just Twitter. The most-popular instance,, is a general-purpose instance with millions of users and no shared interest. But there are a lot of smaller instances on the network as well. There are instances for hobbies like bicycling, photography, and (as expected) a million tech-related niches. There are instances for specific political movements or economic systems. There are instances for marginalized groups, for hate, or for specific parts of the world. These servers make up the long tail users of the network, with some instances hosting less than a dozen people.

When a user signs up at an instance, they get the following:

But there’s something else that instance members get: association. When you sign up as and interact with other people on the network, you implicitly communicate the following:

Joining an instance strongly ties your online identity to that instance. Though it may be unfair, you will be judged by the second half of your handle if your instance has a reputation in the network. If the people on your instance are hateful enough, your instance may end up on one of many popular instance blocklists, and you lose the ability to federate with large chunks of the network. Users who don’t want this to happen need to moderate their own communities and protect them from bad actors.

This is one aspect of Mastodon that I think is not communicated well to newcomers. If you want to stick to having one account on one instance, you need to help moderate the community and keep awful stuff out of it, because you will be judged by how your worst community members act.