I need this. I never really cared about ads and them showing up on websites, I dont mind if that is the way that the site makes its money. However, about two months ago I got a flyer in the mail for a local dentist, so I went to their website. Now every site that I go to has that dentist as the ad and I cannot figure out how to clear cookies/cache whatever to change it (it only happens on my laptop in a certain browser). Anyway, I welcome "do not track" and will definitely use it.