From Google spokesperson Andrea Faville: Our advertising system was designed before the smartphone revolution. It offered user controls and determined ads' relevance, but only on a per-device basis. This past June we updated our ads system, and the associated user controls, to match the way people use Google today: across many different devices. Before we launched this update, we tested it around the world with the goal of understanding how to provide users with clear choice and transparency. As a result, it is 100% optional--if users do not opt-in to these changes, their Google experience will remain unchanged. Equally important: we provided prominent user notifications about this change in easy-tounderstand language as well as simple tools that let users control or delete their data. Users can access all of their account controls by visiting My Account and we’re pleased that more than a billion have done so in its first year alone.