Good artists borrow; great artists steal.
-Pablo Picasso (maybe)
This great article called The Ecstasy of Influence: A plagarism in Harper's Magazine explores the question of plagarism in art- any art- and whether it really is such a black and white issue.
Fascinating stuff. Plagarism, thinly cloaked as "research," occurs all the time in both academic and pop-literature. In academia, we call it "standing on the shoulders of giants;" in popular publishing, we call it "stealing." Did black blues musicians rip off negro spirituals and Irish folk music? Did Elvis rip-off black blues musicians? Did the Beatles rip off Elvis? I'm sure you can think of about 1,000 movie equivalents here.
Does any of this matter? You be the judge.