from Hacker News

Spammers have figured out a way to suppress comments on twitter by dumping a bunch of hidden comments in response to a comment. Think of it like negative SEO. Twitter interprets the influx of comments as spam and hides the post *which the comments are replying to. Because the accounts are private it is impossible to know what was posted, but it could be links to pornographic websites or contain vulgar language in order to trigger the spam filters and force twitter to hide the parent post.

But the point it, such censorship is possible. This can be used to suppress negative reviews, political dissent...anything, provided you know which type of spam comments trigger the post to be hidden. It can be done to anyone and you will not even notice unless you log out and check from another account.

Two videos showing that it is possible, but how it is possible is unknown unless you know what messages were posted and the type of account that posted them.

https://streamable.com/ucl5a4 (Elon Musk)

second video showing the same thing, but with spacex (not as detailed)

https://streamable.com/b3pol6

An Elon Musk spammer is using this method on another spammer. You can see how the comment vanishes after getting 12 of these comments. It is not visible anymore. This can be used on any comment in theory, not just spam ones.