The issue in this case is whether the developers of peer-to-peer file sharing software can be held liable under copyright laws if their software is used by some consumers to exchange copyrighted materials even though it also has substantial non-infringing uses that are likely to grow over time. The position taken by the Court below, and by the ACLU in its amicus brief, is that copyright enforcement should be targeted at those who actually violate the copyright laws and not at software developers, and that stifling technological development will ultimately diminish the marketplace of ideas on the Internet.