Privacy: what's different now?

Modern computing technology makes it possible to record, preserve, collate, reconstruct, and use detailed facts about individuals on a scale and in a style quite different from the past. With this technology, data is voluminous, not sparse; is permanent, not transient; and is detached, not tied to the individual's own observation. How do these developments change the reality, or the perception, of privacy for the individual? How, in particular, do they change the reality or perception of privacy for daily life, not just in legal situations or in relations with authority? This paper examines the properties of current computing technology, illustrating their consequences for personal data, and argues that they have profound implications for personal privacy and autonomy.