You can trust them to respect it about as much as you can trust them to respect the opposing proposition, which is their "opt out cookie." The point is that it

You can trust them to respect it about as much as you can trust them to respect the opposing proposition, which is their "opt out cookie." The point is that it puts the onus on them. The EFF explains this much better: https://www.eff.org/deeplinks/2011/02/what-does-track-do-not-track-mean https://www.eff.org/deeplinks/2011/02/what-does-track-do-not... This isn't to make anyone untrackable. This is to make a far more consumer-friendly opt-out mechanism among those that are participating voluntarily. If it becomes legislation, which is what is being debated, then it is somewhat like a DMCA for users. If an advertising company tries to circumvent it, they are acting illegally. This isn't a silver bullet for privacy, but it is really powerful.