Most people think that DRM is evil, and I mostly agree. The main argument against DRM is that it could take the control out of the computer owner's hands. But I think that there is one good thing that could come out of it: the creator of the content decides in what ways is it allowed to use it or not. The "only" problem with this is where the control of the use of the content stops and control of the computer begins.
So what happened that made me wish have DRM? I have sent a mail to someone, and that person put another one into CC: when replying. I didn't want the mail to be CC'd or BCC'd. It was supposed to be a private mail. But there is no way that I can enforce it. I did not even dare to ask the original recipient NOT to put anyone in CC: when replying, because I know him. He's pretty sloppy and he could have forgotten to delete the relevant parts of the original message (where I ask for it not to be CC'd) in addition to CC:-ing the reply, which would make things very bad.
OK, this time no damage was done, because I half-expected up front that the recipient will CC his reply, so I was careful about what I was writing. But the question remains - how can you, with the current technology, enforce such policies and make sure that the private communication remains private? Currently, the written communication in any form (esp. digital, like emails) is, most often, a silent agreement of parties. The fact is that once the document leaves the creator's supervision, receiving parties can do anything they want with it.
Most of the time silent agreements about privacy work well. I think it is so because of the mutual interest that all parties have in keeping the communication private. Sometimes, as happened to me, they fail, i.e. there is a discrepancy between communicating parties in what should be held private, or a difference in perceived mutual interest.
If I had some kind of DRM, I could just mark my mail as "for your eyes only" and forget about the problem. I'm interested in other opinions - how do you (try to) solve this problem?