About posting copyrighted articles -

My friend at work and I took up the friendly debate about copyrights. He took the side that it is in violation to post a copyrighted article and I took the opposing. Although we came up with many gray areas, my friend was unable to give a reason how posting a legal copy of a copyrighted article is a violation of a copyright. So based on our debate, I conclude that as long as you have a legal copy of an article, it is ok to post it on a bulletin board.