Despite the increasingly sophisticated software designed to insure privacy online, there is an astonishing lack of security, report Jennings and Fena, cofounders of Truste, a company involved in promoting Internet privacy. According to the authors, any information transferred over the Internet can easily be accessed by hackers, criminals and private businesses. (The hundredth window refers to the notion that if you lock 99 out of 100 windows, a thief will enter the 100th.) The book explains in detail how Web site marketers, service firms and recreational sites obtain and use consumer information. While future federal legislation may provide more protection, it is up to consumers to actively protect their personal data for now. According to the authors, the Web sites with the best privacy policies include Yahoo, Excite, IBM and Playboy, while sites such as J. Crew and Penthouse do little to reassure online visitors that their privacy is being protected. Jennings and Fena suggest looking for Web sites that prominently display their privacy policies and advise against posting full names in e-mail addresses.