What happens when I flag a posted answer as not an answer? Is the answer put into a review queue? Or will it be deleted?
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When you flag an answer as "not an answer" (or as "very low quality"), two things happen:
If the answer has not been previously reviewed, and is not accepted or locked, it is added to the Low Quality Posts review queue.
In any case, the answer is also added to the ♦ moderator flag queue. This flag will appear in your flag history.
At this point, if the answer has entered both queues, there's basically a race between the LQP reviewers and the ♦ mods to see who gets to determine the fate of the answer:
If the review task completes before a moderator handles the flag, the flag is automatically removed from the moderator queue.
Depending on the outcome of the review, the moderator flag is marked either as "helpful" (if the reviewers recommend deletion, or the answer is edited from the review queue), "declined" (if the reviewers think the answer looks OK), or "disputed" (if the review ends with no consensus).
In case of a disputed review, or if reviewers recommend deletion but the answer cannot be automatically deleted (e.g. because it has a positive score), a separate moderator-only flag is raised; this flag does not appear in your flag summary.
If a moderator handles the flag, the review task is automatically dismissed. When handling a flag, moderators can choose whether to mark it as "helpful" or "declined".
Note that, while reviewers can only edit or delete answers (or just leave them as is), moderators handling "not an answer" flags have an extra option: they can convert the answer to a comment. However, this is only possible if a moderator happens to handle the flag before reviewers deal with it (which on busy sites like SO is unlikely), and also requires the moderator handling the flag to independently notice that "hey, this looks like it should be a comment!", and to take the extra time to figure out which post it should be a comment on.
References and related posts
If you flag a question as NAA it will end up in the Low Quality review queue if the answer isn't accepted (flags on accepted answers can only be handled by moderators). It will always end up in the moderator's flag queue.
If a moderator handles the flag, it will be either be marked helpful or declined.
The community can handle the flag if it isn't handled by a moderator already (this is how community moderation can be done). If the community handles the flag though the Low Quality review queue, the flag will be marked helpful or disputed.
If the flag is deemed helpful from the review queue, the post can be deleted. Sometimes the post score prevents deletion from the queue. That will trigger a new moderator-only flag.