New Google Tool?

Google already monitors online shopping – and now it’s keeping an eye on physical stores to try to sell more digital advertising. The internet company said that a new tool will track how much money people spend in merchants’ brick-and-mortar stores after clicking on their digital ads.

The analysis will be done by matching the combined ad clicks of people who are logged into Google services with their collective purchases on credit and debit cards. Google says it won’t be able to inspect the specific items purchased or how much a specific individual spent.

But even aggregated data can sometimes be transformed back to data that can identify individuals, said Larry Ponemon, chairman of the Ponemon Institute privacy research firm.