> The exchange of cookies is between you and the ad network, not you and the publisher hosting the ad or you and the advertiser who placed the ad. But my brows

> The exchange of cookies is between you and the ad network, not you and the publisher hosting the ad or you and the advertiser who placed the ad. But my browser could be smart enough to only exchange those cookies (or whatever data format we want to use) based on the current origin I'm visiting. There's no rule that requires me to use the same doubleclick session on CNN and Reddit. If I visit a website that's classified as a news site, at that point doubleclick wants to know information about me so it can hold an auction to show me targeted ads. At that point, the browser could send doubleclick any information -- it could be based on the current origin, it could be based on the time of day, it could be based on what profile/identity I have manually switched on/off. The point I'm getting at is the model of "you have one persistent identity that doubleclick can hook into anywhere" is already broken. Part of choosing how we present ourselves online includes the freedom to have multiple identities and to choose when/how those identities are revealed.