'Cookies' Cause Bitter Backlash

Tools that track users' whereabouts on the Web are facing increased regulatory and public scrutiny and prompting a flurry of legal challenges. Since July, at least six suits have been filed in U.S. District Court for the Central District of California against websites and companies that create advertising technology, accusing them of installing online-tracking tools that are so surreptitious that they essentially hack into users' machines without their knowledge.

All of the suits seek class-action status and accuse companies of violating the federal Computer Fraud and Abuse Act and other laws against deceptive practices. In 2001 and 2003, courts ruled that websites could place small text files called "cookies" on machines. Cookies allow sites to remember users, so they don't have to log in user information on each visit. But they can also be used to track users across websites, compiling a profile of a user's browsing interests. The earlier decisions said tracking across websites was legal. Since then, online tracking has become the foundation of the $23 billion online advertising industry. The industry says tracking tools help subsidize content, allowing many websites to be free to users. The new lawsuits challenge the older rulings because modern tracking tools are more sophisticated than early cookies.