Freakonomics:

Supporters of stronger intellectual property enforcement argue online piracy is a huge problem, one which costs the U.S. economy between $200 and $250 billion per year, and is responsible for the loss of 750,000 American jobs. These numbers seem truly dire: a $250 billion per year loss would be almost $800 for every man, woman, and child in America. And 750,000 jobs – that’s twice the number of those employed in the entire motion picture industry in 2010.The good news is that the numbers are wrong.

Read the article to see why the Freakonomics guys believe that.