That's according to a recent study from Stanford's Center for Internet and Society. While Congress wrestles with online privacy legislation, the status quo is that companies self-regulate how they track users online. Several months ago, some of these self-regulating groups announced they'd use and Advertising Option Icon to let users know whether the site they're on is tracking them or not. Stanford's report finds that 12.5% of the companies in the study are leaving their tracking cookies on even after users try to turn them off. A violation of their policy. While the House holds a hearing Thursday about online privacy, it's unclear whether any lawmaking will actually get done.