Or just ban this kind of data collection. Is there any reason anyone would willingly click "Accept" when a website asks to share your data with 500+ partner sites?
replies(10):
Targeted ads generally bring in 3x the revenue of generic ads. Personally speaking, I'd rather have 1/3rd the ads on a page and allow my data to be tracked. I don't mind my data being tracked, and I'd rather see ads for keyboards / mens clothes (what I buy) than diapers / ladies shoes (who knows what tomorrow holds, but this is not what I'm buying at the moment).
2. Contextual ads are not targeted and would not be showing you adverts for diapers or ladies shoes- unless you are reading about diapers or ladies shoes.