Social Media Blocking Has Always Been A Lie

What does it mean to block someone on a social media site?

Way back in the mists of time, we dealt with trolls on Usenet with the almighty PLONK - PLaced On Newsgroup Killfile. It meant your newsreader never downloaded their posts. They could rant at you all day long, and you'd never hear from them. It's what we would nowadays call "Mute".

But, whether you're on Usenet or a modern social network, muting someone doesn't actually stop them replying to you. The miscreant can still see your posts, interact with them, quote them. And everyone on that service can see their abuse. Perhaps they will also join in?

Most modern social networks now have the concept of "Block". When Alice blocks Bob, it means Bob cannot see Alice's posts. The service doesn't deliver her content to him. If he goes looking, he can't find it. She is invisible to him.

Except, of course, that's a lie. If Bob logs out of his account, he can see Alice's public content. If he logs into an alternative account, he isn't blocked.

The block is a social signal backed up with mild technical restrictions.

What do I mean by that? Ordinarily, you will have no idea that you have been blocked by someone. They will simply vanish from your screens. You do not receive an alert that you've been blocked. Technical restrictions mean you won't see their posts, nor replies to them. The only way you might know is if you deliberately look for the person blocking you.

Seeing that you have been blocked is a "social signal". It lets you know that your behaviour was unwanted, or that your contributions weren't valued, or that someone just doesn't like you. For most people, that sort of chastisement probably induces a little shame or grief. For others, it is enraging.

Again, it isn't impossible for a blocked user to see content - but technical restrictions means it takes effort. And, it turns out, for all but the most obsessive abusers - a mild bit of UI friction is all that it takes for them to stop.

On a centralised social media platform, like Twitter and Facebook, your blocks are private. The only people who know you have blocked Taylor Swift are you, the platform, and T-Swizzle herself.

On decentralised social media platforms, it is more complicated.

Mastodon / ActivityPub lets you block a user. In doing so, you have to tell that user's server that you don't want them seeing your messages. That means your server knows about the block, their server know, and the user knows. But, crucially, there's nothing to stop a malicious server ignoring your wishes. While your server can mute all the interactions from them, there are only weak technological restrictions on their behaviour.

BlueSky / AT Protocol takes a different (and more worrying) approach. BlueSky tells everyone about your blocks. If Alice blocks Bob - the system lets everyone know. This means that if Bob starts replying to your posts, other clients will know to ignore his interactions with you. I've written more about the dangers of public blocklists over on BSky.

But, crucially, none of these systems actually block users. This isn't like that Black Mirror episode where people are literally blurred out from your eyeballs.

In all cases, a user can log out and see your public posts. They can sign in with an alternative account. And, in the case of decentralised social media, they can choose to ignore the technological restrictions you impose.

Social networks have a responsibility to keep their users safe. That means having enough friction to prevent casual abuse.

But blocking is only a social signal. That's all it ever has been. It is a boop on the nose with a rolled up newspaper. It is a message to tell someone that they might want to adjust their attitude.

You should block - and block often. You should feel empowered to curate an environment that is safe for you. But you should also understand the limitations of the technical controls which underpin these social signals.