How 'cookie matching' at Google caused an ad tech divide

Google's most vocal critics have caused a schism among the ad-tech community: One group led by Brave, a rival web browser, claims to have analyzed Google's ad exchange and found sneaky data-sharing with partners. Meanwhile, Google's defenders say rivals are being alarmist about a common industry practice known as “cookie matching,” which is a fundamental component of harnessing data to power internet ad auctions.At the center of the dispute is a study released last week by Brave, whi