I asked this on Quora a couple of months ago: http://www.quora.com/Bitcoin/Would-it-be-theoretically-possible-to-mark-certain-Bitcoins-as-dirty http://www.quora

I asked this on Quora a couple of months ago: http://www.quora.com/Bitcoin/Would-it-be-theoretically-possible-to-mark-certain-Bitcoins-as-dirty http://www.quora.com/Bitcoin/Would-it-be-theoretically-possi...