Is 'Do Not Track' a magic button?

Is a "Do Not Track" button on Web browsers a miracle cure for the tech industry’s privacy woes? Or just a way for Web companies to dodge a privacy law from Congress? Furthermore, will it work?

What the industry gains is valuable: It buys time to show lawmakers it can create and implement a credible new system for responding to consumer concerns about being tracked online. In exchange, companies may avoid a federal law mandating a Do Not Track system. “This is an attempt by the Digital Advertising Alliance and Google to undermine a real Do Not Track system,” said Jeff Chester, executive director for the Center for Digital Democracy. “They are terrified of a system that will not only stop tracking but also collecting data.”