Shadow ban
Form of moderation: an account is blocked without being told. Posts are visible to the poster themselves but not to others; followers don't see updates. Result: poster posts into the void thinking everything is fine.
Reddit + 4chan early implementers (anti-spam against bots). Twitter long denied doing it, then "visibility filtering" was exposed in the Musk-era Twitter Files in 2022. Instagram + TikTok algorithmic suppression (the account doesn't show up in hashtag search, For You feed) is a variant. Hard to 100% prove — maybe your posts are just bad? Detection: have a friend log out, check your profile — if posts are missing, you're shadow-banned. Ethical debate: protects against bot spam but can be used for political censorship.