Charter Communications, the fourth-largest cable system in the United States, has started telling its high-speed Internet customers that it is going to keep track of every site they visit on the Web. The cable company will sell the data to a firm called NebuAd, which in turn will use it to show ads to Web-surfing Charter customers that are meant to be related to their interests. (Visit a knitting site yesterday and see yarn ads today.) Charter started sending letters out to several hundred thousand customers in four markets: Fort Worth, Tex.; San Luis Obispo, Calif.; Oxford, Mass.; and Newtown, Conn. (The letters were first reported by DSLreports.com.)

Charter said it will start testing the system within 30 days and will make a decision whether to roll it out to its 2.8 million Internet customers a few months after that.

Using data from Internet service providers for what the advertising people call behavioral targeting raises all kinds of questions about privacy, disclosure and who owns the information about where Internet users surf.

Full article is here : http://bits.blogs.nytimes.com/2008/05/14/charter-will-monitor-customers-web-surfing-to-target-ads/?ref=technology