Click: What Millions of People Are Doing Online and Why it Matters by Bill Tancer is a scary book! Published in 2008, it "guides the reader through the search patterns among 10 million Internet users, challenging myths and making new discoveries about the psychology of consumers, illustrating that clicks speak louder than words and can reveal unspoken truths about individual drives that are not expressed via other forms of media."

In short, the book explains how your online activity can be captured by experts who can then determine your identity as well as nearly everything else about you! No Breathing Space for extensive web surfers.