Here is an excellent symposium on intellectual property law. There are three speakers including one allied with the Mises Institute who provides an excellent argument against IP altogether. While the other two accept and support IP laws, it is interesting to note what all three do agree on in terms of the history, intent, and historical results are of intellectual property law.
[HT Nancy Prager]
One of the surest tests [of the superiority or inferiority of a poet] is the way in which a poet borrows. Immature poets imitate; mature poets steal; bad poets deface what they take, and good poets make it into something better, or at least something different. The good poet welds his theft into a whole of feeling which is unique, utterly different than that from which it is torn; the bad poet throws it into something which has no cohesion. A good poet will usually borrow from authors remote in time, or alien in language, or diverse in interest.