Like the Incredibles, facing down a nefarious, subterranean villain called “the Underminer” at the end of their debut movie, Mozilla is facing down data miners by giving Firefox users a new, albeit less-than-incredible power. The browser feature will give users the ability to opt out of behavior-based advertising. Websites and ad servers will get a “do not disturb” message via a click-transmitted “do not track HTTP header,” a better approach, Mozilla claims, than cookies or user-blacklists of advertisers.