A friend of mine runs a similar site for music [1]. I can't be sure, but I'm fairly certain he didn't do it because he was interested in pirating music (at least not entirely). He did it because he saw that others were interested in pirating music (er, finding links to music that may or may not be pirated), and that a service helping them do that would be useful/appreciated(/get him noticed).

[1] http://mppp.it