The world does not owe targeted advertising networks a business model, so I am agnostic about Microsoft’s decision to ship Internet Explorer 10 with “Do-Not-Track” enabled by default. Ryan Singel has a good write-up on Threat Level that covers many dimensions of the issue.
Decisions like this are never driven by a single motivation, but I’m interested in the likelihood that Microsoft made this choice hoping to drive a dagger into Google’s business model. To the extent it did, it’s a nice illustration of how competition among companies can serve consumers’ privacy preferences. There is some demand for privacy, though less than most regulatory types believe. Microsoft saw an angle to get some pro-privacy PR, improve consumers’ privacy by a small margin, and hamstring a competitor. You go, girl. Er, Microsoft.
Now, consumers aren’t falling over themselves for protection from the benign practice of tracking for the purpose of delivering targeted ads. I suspect that counter-punches from ad networks and Google will send the Do Not Track header into the dustbin of privacy history right along with P3P. The idea of putting a signal into the header that says “please do not track” is clumsy, to put it charitably.
If you want to avoid tracking, you can do that already. Use Tracking Protection Lists.