Why and how are some questions deleted?

Questions that are extremely off-topic, or of very low quality, may be removed at the discretion of the community and moderators.

Over time, closed questions that are not useful as signposts to other questions may also be removed, as well as questions which have no significant activity over a very long period after being asked. If you want to improve a question to keep it from being deleted, click the "Edit" button beneath it. See the Help Center page "How do I ask a good question?" for more tips on improving questions.

Users can typically delete their own questions (with a few exceptions). To do so, simply click the "Delete" button underneath the question.

You can't delete your own question if one or more of the following is true:

• It has an accepted answer
• It has an answer (that isn't deleted) with an awarded bounty
• Another question has been closed as a duplicate of it

Questions can also be deleted by the community. Moderators can delete any question, and users with 10,000 reputation can cast delete votes on closed questions. It takes 3 votes, minimum, for a user to delete a closed question in this way (with more delete votes required for popular posts, based on the score of the question and its highest-scoring answer). Questions that have been closed within the past 48 hours usually can't be deleted, so as to allow them to be edited and possibly reopened.

Additionally, any post that accumulates enough rude or abusive or spam flags will be automatically deleted. Questions can also be automatically deleted based on a number of other criteria.

What happens when a post is deleted?

Once a post has been deleted, it will disappear for all users except staff, moderators, and users with at least 10,000 reputation. Deleted questions and answers are always visible to their authors, regardless of the author's reputation.

Self-deleted posts can be viewed and undeleted by their original authors. If you delete your own question, you must undelete it before you are able to edit it.

Note that deleted posts do not normally appear in search results. To find questions you posted that are deleted, see the Deleted questions page (which is linked at the bottom of the Questions page of your user profile). In addition, users with the moderator tools privilege can search among their own deleted posts by using the search operator deleted:1 (site moderators can use this to find deleted posts by any user on the site).

Deleted posts can be undeleted by casting undelete votes. Once a question has 3 undelete votes (or more, for popular posts), it will no longer be deleted. (Site moderators can undelete any post singlehandedly.)

For more details about how post deletion works, see this community-curated FAQ on Meta Stack Exchange.