The current state of copyright law gives another example of the distortions to sensible policy that have been growing in our society. Matthew Yglesias has been on this topic a great deal, and should be read and listened to. His most recent posts are here and he links to another author on the subject here. To understand the current state of copyright, and of greater concern where it is headed, read the inspiration for Matt's post, this opinion piece by Mark Helprin arguing for perpetual copyright.
Helprin's view is that it is his natural right that he should have, forever, the sole right to publish any work produced by him. Likewise any other author has, by nature, the same rights. It is societies obligation to protect this right. This position is completely wrong. The protection of a copyright is a special privilege that society grants to the holder. Society grants this right in the expectation of some return, not solely for the benefit of the inventor. It is not an inherent right of the holder's that society is obligated to provide.
In fact, in my opinion, there is no reasonable expectation of any intellectual property right (IP) in nature or in market economics. Recognize that it is the nature of intellectual property that in order to make money off of intellectual property the author needs to get me to pay him money to put a copy of it into my head. It is then that copy, in my head, that copyright law is trying to control. Consider a song, for example. It is of value to the author only if he plays it for me, in one form or another, thus putting a copy in my head. By all rights, I should be able to use that copy for any purpose I choose. The copy in the author's head is, of course, his own to do with as he likes.
The problem then is that in order for an author to enjoy copyright protection he needs to control the use of the copy in my head. There is no inherent right to control that at all. To control that copy you need to have the agreement of society and the authority of a government. Now indeed, the implication of this is that being an author, or writing songs and the like is not naturally a very profitable enterprise. Society, through government, artificially makes it more profitable, but does so in order to derive some benefit to society in general. It is worthwhile to society to artificially make being an author or inventor more profitable than nature or the market makes those activities, so it is a good thing to grant copyright protections for some period of time. But it would be a detriment to society if author's had permanent control over any work that they created.
To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and DiscoveriesThis grant of exclusive right is a special privilege granted "to promote the progress of science and the useful arts" and it granted "for limited times".
Mark Helprin takes a quite different, and I would say quite selfish point of view. He believes that society is obligated to him and to his descendants a perpetual control over any work he has generated. Despite the fact that controlling the use of an author's work requries the cooperation of government and society, and requires generations of individuals to agree to not make use of ideas in their own heads, ideas that they might well have paid money to acquire, Helprin feels that the wealth generated is entirely his and nothing is due him in return. The obligation, in Helprin's mind is a one way street. The rest of society needs to grant him sole use of these ideas, in return he owes nothing. That one way street, is, I believe, very much in the nature of today's conservatism.