Should e-Books Be Copy Protected?

I guess the subject here can be replaced with any other sorts of digital downloadable products lile mp3, music, movies and videos.

There doesn't seem to be any harm. Those who are already thinking of buying it would continue to do so, and those who have no intention will just go for the pirated version anyway. It's not as if the content can't be found on any other websites other than the publisher/distributor.