antispam for 4chan

Is it possible to make an automatic anti-spam based on the report feature?

Maybe add an extra option.
O Rule breaking posts
O Illegal content
O Spam

It will check for similar posts in all boards, if more than one post with a similar composition were reported as spam by a X number of users it will be flagged as spam deleting all similar posts and blocking it to be posted again. Something similar to the gmail anti-spam.

Maybe it could use some kind of captcha to avoid this feature of being abused.

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O Rule breaking posts
O Illegal content
O Spam [captcha]
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Also, when X people report a spam post it will search for all posts XX% similar to it already reported and flag them with a (is this spam? Report Yes/No) as an aid to save autentic posts (if many people report it as non spam it might be saved) and them add the spam posts to a spam database.