Google Maps is one of the world's favorite ways to figure out how to get from place to place. Now you can expect more billboards along the way.

In a blog post this week, Google told the world that local businesses can now offer coupons on Google Maps almost as quickly as you grab directions via the app.

The company is rolling out a new tool for advertisers that lets them link discount offers to Google Maps searches with just a few mouse clicks. These offers will appear next to a blue tag in Google's search results, and the advertiser pays when you save coupons – what the company calls Google Offers – to your smartphone.

While coupon-clipping might seem too low-tech for Google, the new tool is dream come true for advertisers. They can target potential customers who may very well be driving by their store at that moment – they don't even have to rely on someone actually typing in the name of their business. That's a uniquely powerful proposition for nudging someone through the door.

In a way, location-based advertising feels even more potent than Google's core search-based ad product. Google ads can often seem deeply irrelevant when you're searching for information that has nothing to do with a possible purchase. But the world outside your door is inherently commercial: Where people come together, commerce takes place. For businesses, a coupon on Google Maps is the digital equivalent of hanging a sign in your window.

Image: Google

This deep integration of coupons and maps comes as Google ramps up its own foray into direct-to-shopper physical commerce. At the moment, Google Shopping Express, the company's same-day delivery service, is only available in the San Francisco Bay area. But imagine Shopping Express at scale: Google now has a way to make money off people's consumer decisions whether they leave the house or stay home.

In many ways, Google is positioning itself to combat Amazon, as both companies encroach ever further into each other's prime territory. If Google can use its maps to convince people to buy from local stores, that's one sale Amazon doesn't make. And Google's same-day delivery, which relies on inventory at local chain stores such as Target and REI, enlists Amazon's retail rivals in an alliance against a common foe.

In the end, Google needs to do whatever it can to keep users on Google. Product searches and purchases on Amazon are eyeballs not on Google – eyeballs not on Google's true inventory: ads. If you're looking for directions to a friend's house and Google can steer you to pick up an extra bottle of wine along the way, that's not just nice for the wine store – that's a few more bucks not going into Jeff Bezos' pocket.