"The term 'spyware' is not well defined. Generally it is used to refer to any software that is downloaded onto a persons computer without their knowledge. Spyware may collect information about a computer users activities and transmit that information to someone else. It may change computer settings, or cause 'pop-up' advertisements to appear (in that context, it is called 'adware'). Spyware may redirect a Web browser to a site different from what the user intended to visit, or change the users home page. A type of spyware called 'keylogging' software records individual keystrokes, even if the author modifies or deletes what was written, or if the characters do not appear on the monitor. Thus, passwords, credit card numbers, and other personally identifiable information may be captured and relayed to unauthorized recipients...A central point of the debate is whether new laws are needed, or if industry selfregulation, coupled with enforcement actions under existing laws such as the Federal Trade Commission Act, is sufficient. The lack of a precise definition for spyware is cited as a fundamental problem in attempting to write new laws that could lead to unintended consequences. Opponents of new legislation further insist that, if legal action is necessary, existing laws provide sufficient authority. Consumer concern about control of their computers being taken over by spyware, and resulting impacts on their privacy, leads others to conclude that more legislation is needed. The FTC supports S. 1608, which would enhance FTC enforcement against spyware, focusing on cross-border fraud."
CRS Report for Congress, RL32706
United states Department of State: http://fpc.state.gov/