Think Google only has their eyes on you when you're online? Think again...

FOX's Tom Rigatti explains:

Google is keeping track of what you're buying offline, in addition to monitoring your online shopping in its latest attempt to sell more digital advertising.

The offline tracking of most credit and debit card transactions will help Google to automatically inform merchants when their digital ads translate into sales at a brick-and-mortar store.

Google believes the data will show a cause-and-effect relationship between online ads and offline sales. If it works, it could help persuade businesses to increase their digital marketing budgets.

Google's online ad network generated $79 billion in revenue last year. The leader in the industry.

Tom Rigatti, FOX News.