Targeted Ads: What They Are & How They End Up On Your Devices

MINNEAPOLIS (WCCO) -- Shopping for holiday presents in secret isn't so much of a secret anymore, thanks to online ads that target multiple devices on a shared wireless router.

For example, if a parent is using his or her laptop to buy their kid a pair of skis, the shopper might notice ads popping up on that laptop, showing those skis or the company that makes them. Those ads could also come up on their spouse's laptop, their child's phone, or any other device connected to the same WiFi.

The reason why, according to cybersecurity expert Brad Nigh from the firm FRSecure, is because WiFi routers each have an IP address, which serves as a geographic footprint. As far as the Internet is concerned, every phone, tablet, and computer using that WiFi is coming from one place.

The cookies that follow shoppers around from website to website are all sending ad information to your device, which then relays it to your router.

"They're just targeting that IP address," Nigh said. "And then if you have the same type of device, so if you both have an iPhone 8 with the same browsers [and the] same updates, they're going to look at that and go, 'That's probably the same device.'"

He says it's generally difficult for consumers to work around that pattern, besides browsing in incognito mode.

"That'll help eliminate some of those ads because it doesn't track the cookies as much," Nigh said. "That's how they track those devices."

Browsing incognito isn't always ideal while shopping because doing so means the browser has no memory, meaning the consumer to re-enter login information, card numbers and billing addresses for every website.

Another option, which becomes more ideal as the holiday approaches, is to shop in-store.