Implement "flag as spam" in the forums
This would hopefully eliminate the need for the "Spam and malware" topic. Also, a better system to actually follow through and remove spam (eg. I've personally had spam in comments of one of my scripts for weeks, I flagged it and posted on the forums and it's still not been removed - http://userscripts.org/scripts/show/9580#comment-38856).
There is review spam as well: https://userscripts.org/users/438451
Paolo Brocco commented
Please consider also an automatic way to fight spam (without somebody to manually click/report it) e.g. with akismet, see my idea (and vote it) here: http://userscripts.uservoice.com/forums/795-general/suggestions/2618223-implement-akismet-for-automatic-comments-spam-filt
We already have a script that automates this for us, but having implemented in the site itself would be much better for everyone.