<P> with casual content delivery networks: total cost = filesize × customers × cost - per - byte (\ displaystyle (\ text (total cost)) = (\ text (filesize)) \ times (\ text (customers)) \ times (\ text (cost - per - byte))) </P> <P> The economic effect of copyright infringement through peer - to - peer file sharing on music revenue has been controversial and difficult to determine . Unofficial studies found that file sharing had a negative impact on record sales . It has proven difficult to untangle the cause and effect relationships among a number of different trends, including an increase in legal online purchases of music; illegal file - sharing; drops in the prices of CDs; and the extinction of many independent music stores with a concomitant shift to sales by big - box retailers . </P> <P> Also many independent artists choose a peer - to - peer file sharing method named BitTorrent Bundle for distribution . </P> <P> The MPAA reported that American studios lost $2.373 billion to Internet piracy in 2005, representing approximately one third of the total cost of film piracy in the United States . The MPAA's estimate was doubted by commentators since it was based on the assumption that one download was equivalent to one lost sale, and downloaders might not purchase the movie if illegal downloading was not an option . Due to the private nature of the study, the figures could not be publicly checked for methodology or validity, and on January 22, 2008, as the MPAA was lobbying for a bill which would compel universities to crack down on piracy, it was admitted by MPAA that its figures on piracy in colleges had been inflated by up to 300% . </P>

Where did these networks get the name p2p