"The Stanford Persuasive Technology Lab creates insight into how computing products -- from websites to mobile phone software -- can be designed to change what people believe and what they do." This unusual field of study is called captology, and the subject is explored in detail on the lab's homepage. The Key Concepts section provides a brief overview of captology and links to another page with nine topic papers published by researchers at the lab. In a series of examples demonstrating how computers can be used to influence a person, the site's creators separate instances into macrosuasion and microsuasion. Specific websites and computer programs are highlighted to reveal these interesting marketing or motivational tactics.