There's movement from the Internet Advertising Bureau, they explicitly say that this signal must be adhered to if the header is present, and this signal must be forwarded to Demand Side Platforms.
I mean is there any movement in getting major browsers to adopt this?
Normally when a spec. like this is written that needs adoption from web browsers, an explainer is written and then the major rendering engines are asked for their feedback. For instance, here’s an explainer:
I tried to find where this was done for GPC and couldn’t find anything. Did they just write a spec. and not bother doing any of the work involved in getting it adopted? Or is there progress being made that I didn’t see? Hence my question: Is there any movement on this at all? Or is the process of getting it adopted by Blink and WebKit at absolute zero?
