bluGill parent
But others use it as a signal. You are easier to track by the dishonerable with it. Meanwhile the honerable were probably not tracking as much [no way to tell but a reasonable guess]
You might be easier to track with it, but it is not hard to end up with a unique signature anyway. I can already be uniquely identified, so sending "Do Not Track" only has potential upsides. I have seen websites that claim to honor it so it seems to be doing something and I wish they wouldn't remove it.