I have been spending a lot of time on Mastodon lately.
Let me rephrase that. I have been spending a lot of time in the Fediverse lately. Or, should I say on ActivityPub? Anyway, my experience so far has been almost exclusively as a member of the fediverse via my single-user instance running Mastodon, although I am considering many other ActivityPub implementations as well.
An important aspect of the fediverse are the acts of federation and defederation, meaning the way in which different instances exchange information with each other and the level of control that instance administrators have over that process.
In Mastodon, it is possible to block or limit individual accounts on other instances, for example to mute posts from a given account for a time but still keep following them, or to block an account completely and attempt to stop them from following your account.
It is also possible to block on an instance level, both completely severing all contact as well as limiting posts originating from that instance.
Earlier today I got involved in a lot of debate around defederation, specifically regarding the mastodon.se instance and its moderation policies. For more back-story on this I recommend reading the sequence of posts by @Coeur66 that led to me limiting posts from mastodon.se.
In debating this topic, there is a point of view that keeps cropping up which I fundamentally disagree with, and feel like I need to address: The idea that defederation is an act of censorship, and that defederating from an instance is limiting the free speech of the accounts on that instance.
In my view, federation is a voluntary act. As an instance, we choose who we communicate with based on who they are and how they manage their communications in turn. Each instance is its own island, connected only by choice. That choice is the fundamental unit of freedom here, not the freedom of having unlimited means of communication. If an instance is managed poorly, or hosts accounts that harrass or otherwise trouble those of another instance, that instance should be defederated as a safety measure, until its mode of communication is deemed acceptable. Or not. Again, federation is voluntary and can be revoked for any reason.
In the fediverse, there is no central authority and no capacity for large scale content moderation in the same way that is performed by the large corporate social networks. Instead, there is a confederacy of free actors choosing to inter-communicate or not, based on whatever conditions suit each individual member. Participation in that confederacy is voluntary, and to act in a way that causes the other members of the federation to cease communications is an active choice.