Based on what I expect are some pretty sparse data points on the above, it's easy to conclude that online ad targeting is a function maximized in the interests of all parties. We as an industry have proceeded on this unstated assumption for a while now, taking advantage of every new technology, data source, and algorithm in our efforts to maximize the targeting of online advertising.
Something changed recently, though, and it doesn't seem like we as an industry have come to terms with it just yet. It all started when it came to light that ISP-based tracking systems like Phorm and NebuAd had been selling users' browsing history to advertisers unbeknownst to those users. Even I find that a little creepy, and it turned out the Federal government did as well.
