Last spring, the public got a firsthand look at spyware's pervasiveness when it was discovered that peer-to-peer file-swapping app Kazaa was bundling a program designed to form a giant distributed network -- composed of Kazaa users' computers -- that could transmit information back to Brilliant Digital Entertainment, the company that created it. In effect, this network would use people's computers to perform work for Brilliant Digital. The program had been distributed with Kazaa since the fall of 2001, according to a document that Brilliant filed with the U.S. Securities and Exchange Commission (SEC) in April. Even though Brilliant said it...