When you see "[deleted]" or "[removed]" under a username, what exactly happened?

The labels "[deleted]" and "[removed]" both appear in place of usernames or post content in Reddit threads, but they indicate two different things and it is important to distinguish them. "[Deleted]" indicates that the user themselves took an action: either the user deleted the specific post or comment voluntarily, or the user deleted their entire Reddit account. When a user deletes a post or comment, the username is replaced by "[deleted]" in the thread. When a user deletes their account, all their posts and comments across Reddit have their username replaced by "[deleted]" as well, though the content itself may remain visible. In either case, the initiative was with the user. "[Removed]" indicates that a moderator or Reddit's automated systems (AutoModerator) took the content down — the user did not delete it themselves. When a post or comment is removed by a moderator, the content is hidden from general view in the subreddit feed and in the thread, replaced by "[removed]" or a moderator note explaining the reason for removal. Moderators can remove content for violating subreddit rules, being off-topic, being low quality, or for any other reason within their discretion. Reddit's AutoModerator system can also automatically remove content that matches certain criteria (keywords, account age thresholds, karma minimums) before any human moderator reviews it. A removed post still technically exists in Reddit's database and can be reviewed by moderators and Reddit administrators, unlike a deleted post which the user has chosen to expunge. From a practical standpoint, if you see your own comment replaced by "[removed]" without having taken any action, it means a moderator or automated system removed it rather than it being a technical glitch.