Bruce Schneier writes:
Governments and corporations gather, store, and analyze the tremendous amount of data we chuff out as we move through our digitized lives. Often this is without our knowledge, and typically without our consent. Based on this data, they draw conclusions about us that we might disagree with or object to, and that can impact our lives in profound ways. We may not like to admit it, but we are under mass surveillance.
Read more of the excerpt from his book, David and Goliath: The Hidden Battles to Collect Your Data and Control Your World, on Wired.