Unless i constrain myself this will sound like one of Gordon Ramsays shows... ;-)
Fu blo he. It's fung time to do something about those bloo videos that stu people are carpet bombing Instructables with. !
Please limit the possibility of posting an unlimited amount of instructables/slideshows/videos per 24 hour period. One (1) per 24 hours are quite enough for anyone that are actually doing something good and not just carpet bombing/spamming crappy videos from Metacafe to get some money.
As a temporary solution maybe just banning Metacafe-videos would help remove those obnoxious spammers. Or can you also get payed by videos on Youtube/Google?
Talking in friendly manner to these guys doesn't really help. It only fixes (possibly) the problem with one guy, but there will just come more and more of them all the time.
(The image of Gordon is stolen from telegraph.co.uk - sorry about that...)