Increasingly, computers are a part of even the most ordinary and simple aspects of human existence. Computers have changed forever how we work, learn, shop and seek information. They have also, since the 1960s, been programmed to monitor and analyze in various ways the interaction between humans and themselves. The rapid development of the World Wide Web in the 1990s has given new life, direction and urgency to this enterprise. This work describes the myriad ways, benign or malign, in which computers are used to monitor people's use of computers. Four distinct contexts for monitoring are examined: formal learning environments (e.g., educational software); information seeking environments (e.g., online library catalogs); the workplace; and the Internet (e.g., online shopping). Computerized monitoring often is called an invasion of privacy, and the conceptual and ethical dimensions of confidentiality and privacy in virtual environments are explored at length. In addition to providing information about the various computerized monitoring tools and techniques, this work focuses on the broader social, conceptual, ethical and legal implications.