Book excerpt: Library computer users are often novices and may not be aware that even seemingly innocuous information supplied to Web sites can be mined by government agencies, unscrupulous businesses, and criminals. Even the donated computers that libraries accept and pass on to otherwcan reveal confidential information like social security numbers. The recent discovery that online service providers have been supplying vast quantities of data to government agencies without the public's knowledge dramatically brought this threat to light. This book will help you, as a librarian, understand the threats and pitfalls of electronic privacy and develop a solid plan to protect the privacy of your patrons.