The iOS 9 version allows users to install 3rd-party ad-blocking apps that control what content is allowed to display and run inside Safari. This includes blocking social widgets such as Facebook's "Like" and "Share" buttons.
Every new technology can be used for good or ill. Such is the case with the newly developing field of behavioral biometrics, a technology that's not the same as the physiological "biometrics" many of us know well. The chart below differentiates the two categories.
Whether or not you support Do Not Track legislation, the success of the industry self-regulation program is vital. What credibility will any industry effort in this area have if one that has received so much focus doesn't succeed?