Man... Mozilla could've been it's own Google if they wanted to be. Maybe they even would've had the clout to produce a privacy friendly ad network. What a wasted opportunity.
Given that the ad industry is filled by the kind of people who are vocally hostile to privacy (especially when it comes to "targeting ads"), this is a product without a market.
AIUI, web sites that host ads probably want the ads to be shown so they can get their money. And people who buy ad space probably want the ads to be shown so they can market their product or service. And maybe the ads will be shown if users white list ad networks that respect privacy.