Targeted Ads -- How Do They Know?

[Gman]

Do you ever use your phone on your home WiFi?

The traffic for all of your devices is sharing the same public IP address from your ISP. Google and the like can then correlate all of your devices to YOU. If you look for something on your phone away from home, they already know who you are and will feed you the same marketing on your devices at home.

Many of our devices are listening to what's around us, and there are little programs that take what they hear and feed it to back-end systems. There is even cross communication between devices using inaudible communication.

This is from 2015 - Beware of ads that use inaudible sound to link your phone, TV, tablet, and PC

The adage is, If you're getting something for free, YOU are the product.