UPDATE: Twitter has rolled back the changes to its blocking system "after receiving feedback from many users." The original post explaining the changes, and the backlash, is below.
Posts claiming that Twitter has reset all of its users' blocks — or "unblocked" everyone — are flooding the site:
A rumor to this effect came and went about six months ago. It wasn't true. And generally speaking, this rumor isn't true either. People you've blocked are still blocked, and vice-versa.
There is, however, a good reason for the misunderstanding: Twitter has substantially changed how blocking works, and what it means.
Before, blocking someone served two main functions: to hide that person from your feed, and to make it harder for that person to look at yours. A blocked user would be invisible to you and you would be less visible to him. The account would no longer be able to follow you, but a dedicated reader could still find ways to view your feed. Logging out of Twitter, for example, would usually work.
It was a hard block, and an aggressive one — people could easily tell if they had been blocked. But a recent change altered the dynamic in some subtle but significant ways. Here's what Twitter says about blocking now:
If your account is public, blocking a user does not prevent that user from following you, interacting with your Tweets, or receiving your updates in their timeline. If your Tweets are protected, blocking the user will cause them to unfollow you.
Some time ago I was blocked by Twitter's CEO after repeatedly showing up in his timeline with my obnoxious animated avatar. I was made aware of this when I realized I wasn't following him, and tried to follow him again. Twitter wouldn't let me, and made clear in many ways that I had been blocked.
Under the new system, however, I am free to follow him, or retweet his tweets. I can interact with him like any other Twitter user, with one difference: he can't see me, or anything I say. If I didn't already know I was blocked, I would have no easy way to tell.
In other contexts, this is called shadow banning or hellbanning. On a forum, a shadow ban is a special kind of torture — it takes the user a while to realize that the ban is in place, because everything seems to be functioning fine. His posts, however, are invisible. This is usually reserved for the most loathsome offenders
This change essentially turns the "block" button into a muting feature. (Twitter "blocking" was and is a bit of a misnomer; a "blocked" user could and can still read your tweets, since they're public.)
The backlash was swift, and centered around harassment:
This is true: It is slightly easier for someone you have blocked, such as a stalker, to read your tweets than it was before the change. But it was very easy then, too, and there seemed to be a lot of misapprehension about this. Blocking, by constructing notional barriers, provided a false sense of privacy. The only way to fully isolate your feed from someone else, still, is to take your account private; your abilty to deal with a harrasser now falls to Twitter's somewhat new and opaque reporting function.
Backlash against the change is gathering under the "#restoretheblock" hashtag, where users that have suffered harassment on Twitter are making the case that the feature is a regression. Chief among the issues is this scenario: that a blocked harasser can now retweet your posts to an audience of people that you haven't blocked, leading to more harassment. The old blocking system didn't fully prevent this either, but the new one makes it easier.
Twitter's line on the harrassment issue, for what it's worth, is that making blocking less apparent to the blocked user makes retaliation less likely.
In any case, what blocking does is at least a little easier to explain: it filters your feed. Blocking is no longer an assertive act that sends a clear "I don't want to talk to you" message, or a way to make viewing your content more difficult. It's a quiet button. Perhaps that what it should be called.
8:34 EST: Updated throughout for clarity, with new feedback from Twitter.