"billboard" cautioned that this research looked only at the pre-release period and not continuous file sharing following a release date. "the problem in believing piracy helps sales is deciding where to draw the line between legal and illegal ... implicit in the study is the fact that both buyers and sellers are required in order for pre-release file sharing to have a positive impact on album sales. without itunes, amazon and best buy, file-sharers would be just file sharers rather than purchasers. if you carry out the 'file sharing should be legal' argument to its logical conclusion, today's retailers will be tomorrow's file-sharing services that integrate with their respective cloud storage services."