Google now knows when its users go to the store and buy stuff

Google will begin using data from billions of credit and debit card transactions — including card numbers, purchase amounts and time stamps — to solve the advertising juggernaut’s long-standing quest to prove that online ads prompt consumers to make purchases in brick-and-mortar stores. The advance, which enables Google to tell retailers how many sales they created through their digital ad campaigns, is a step toward what industry insiders have long described as the “holy grail” of digital advertising. If effective, the program could help persuade marketers to choose Google’s services over the television advertising that still gobbles up the lion’s share of retailers’ ad budgets. “Google — and also Facebook — believe that in order to get digital dollars from advertisers who are still primarily spending on TV, they need to prove that digital works,” said Amit Jain, chief executive of Bridg, a digital advertising startup that matches online to offline behavior.