Illegal file-sharing by US youth has dropped sharply in the past few years, a new study sponsored by the Business Software Alliance has found – though music remains the biggest reasons for P2P file-sharing. The percentage of US 8-to-18-year-olds “who acknowledged illegal downloads of software, music, movies or games fell from 60% in 2004 to 36% in 2007, Australian IT reports. Last year it was 43%. The reasons? Accidentally downloading a virus (62%), getting into legal trouble (52%), downloading spyware (51%), and getting into trouble with one’s parents (48%). “The survey found 66% of young people said their parents set rules on what they could do on the Internet.” Another study, by NPD Group, found that “unauthorized sharing of digital music remains a huge issue for the global music business,” but maybe now not so much from file-sharing as from CD-burning, ArsTechnica.com reports. Then you read headlines like: “P2P breaking Internode’s bank” about how the Adelaide ISP is struggling to keep up with file-sharing customers’ demand for bandwidth (in Australian IT).