@mcc as far as I know, they refer to different approaches. I do not know all the details, but I think the Google approach is monopolistic, while the Mozilla/W3C attempts to keep something workable that is not confined to one ad network in control of the browser. But - not 100% sure. I am pretty sure that the Mozilla setting is not the same as what Chrome uses.
@arjen I don't think my concern about the technology is the chain of custody for the data. I don't want the data to be collected by my browser, and I don't want the people receiving the data to receive it. How hackable the part in between is is, uh, I guess important, but to my mind it is more important to eliminate the technology completely in every single form it exists in.