"Between 2007 and 2011, a period when U.S. civilian employment was essentially flat, the number of jobs that rely on the U.S. ad-supported internet doubled to 5.1 million, according to Economic Value of the Advertising-Supported Internet Ecosystem, a study commissioned by the Interactive Advertising Bureau (IAB). The ad-supported digital industry directly employs 2 million Americans, and indirectly employs a further 3.1 million in other sectors. Calculating against those figures, the interactive marketing industry contributed $530 billion to the U.S. economy last year, also close to double 2007 figures that placed it at $300 billion. These are the key findings that analyze the economic importance, as well as the social benefits, of the Internet. The study, commissioned by the IAB was produced by Harvard Business School professors John Deighton with Leora D. Kornfeld, Research Associate, Harvard Business School, serving as principal investigator. The study was designed to provide an impartial and comprehensive review of the entire Internet economy and answer questions about its size, what comprises it, and the economic and social benefits Americans derive from it."