The NPD Group attributes the drop to an injunction issued last October requiring Limewire to disable its file-sharing software. U.S. District Court Judge Kimba Wood ordered the shutdown several months after ruling that the site infringed record labels' copyright by inducing users to download pirated music.
One year before the court-ordered takedown, Limewire was used by more than half, 56%, of people who downloaded music on peer-to-peer services, according to NPD.
Still, Limewire's shuttering doesn't necessarily mean that music-sharing will permanently wane. For one thing, other file-sharing programs like Frostwire and u-Torrent rose in popularity after Limewire stopped offering the software, NPD reports.
Even more significantly, Web users need not rely on file-sharing programs to download infringing music and movie files. Digital hosting sites like rapidshare.com, megavideo.com and megaupload.com also allow people to share unauthorized versions of songs, TV shows, movies, games and other material.
A study last year by MarkMonitor found that such sites -- which the company dubbed "digital piracy" sites -- garner more than 53 billion visits a year. Unlike Napster, Limewire, Grokster and other peer-to-peer sites, however, the hosting companies haven't been ruled illegal. In fact, one federal judge declined to issue an injunction against Rapidshare, which was sued for copyright infringement by adult entertainment company Perfect 10. U.S. District Court Judge Marilyn Huff in the Southern District of California ruled that Rapidshare -- which allows users to upload large files to a site with a unique URL -- didn't appear to contribute to piracy by users.