“Do Not Track” needs to be defined and then there needs to be a standard as to what obligation a website has to obey the request.
Without a definition or an obligation this is meaningless.
But once fleshed out, this could be a big blow to online advertisers…
I see a Facebook play here too (FB and MS seem to be friendly) - if you are logged into Facebook and the site you are on uses Open Graph, then cookies and other traditional tracking methods become unnecessary. And by logging into FB you are essentially opting in to their Open Graph tracking.
Now imagine FB serving ads against that data while the other other ad networks have no data to work with.
Of course perhaps FB would need to obey Do Not Track as well in that scenario, but it all depends on how it is defined.
A dangerous game.