Mark Bergen:

Google paid Mastercard millions of dollars for the data, according to two people who worked on the deal, and the companies discussed sharing a portion of the ad revenue, according to one of the people. The people asked not to be identified discussing private matters. A spokeswoman for Google said there is no revenue sharing agreement with its partners.
 
 A Google spokeswoman declined to comment on the partnership with Mastercard, but addressed the ads tool. “Before we launched this beta product last year, we built a new, double-blind encryption technology that prevents both Google and our partners from viewing our respective users’ personally identifiable information,” the company said in a statement. “We do not have access to any personal information from our partners’ credit and debit cards, nor do we share any personal information with our partners.” The company said people can opt out of ad tracking using Google’s “Web and App Activity” online console. Inside Google, multiple people raised objections that the service did not have a more obvious way for cardholders to opt out of the tracking, one of the people said.