What does it mean to be shadowbanned vs. banned from a single community?

A shadowban and a subreddit ban are fundamentally different types of account actions with very different scopes, origins, and consequences. A shadowban is a platform-wide account action taken by Reddit's paid administrators (not by community moderators), which causes a user's posts and comments to be automatically removed across every subreddit the moment they are submitted, while allowing the banned user to continue using Reddit as if nothing has changed. The user sees their own posts and comments as though they exist; from everyone else's perspective, nothing they submit is visible. This design is specifically intended to frustrate spammers and bots into wasting effort on content that reaches no one, rather than alerting them immediately that their account has been identified. Shadowbanning is not announced to the user, does not trigger an obvious error message, and can only be detected through the checking methods described above. Only Reddit administrators can issue or remove shadowbans, not individual subreddit moderators. A subreddit ban, by contrast, is a localized action taken by the volunteer moderators of a specific community. When you are banned from a subreddit, you receive a private message from the subreddit's modmail informing you of the ban and optionally explaining the reason. A subreddit ban prevents you from posting or commenting in that particular subreddit but has no effect on any other community on Reddit. You can still use the rest of Reddit normally. Some subreddits additionally offer the ability to "mute" a user, which prevents the user from sending modmail to that subreddit's moderators for a period of time, though it does not prevent them from posting. Subreddit bans can be temporary or permanent, and moderators have full discretion in issuing them within Reddit's Moderator Code of Conduct.