How Ads Follow You from Phone to Desktop to Tablet

Advertisers are increasingly using technology that targets users across multiple devices, and its working.

Imagine you slack off at work and read up online about the latest Gibson 1959 Les Paul electric guitar replica. On the way home, you see an ad for the same model on your phone, reminding you this is the most desirable Les Paul ever. Then before bed on your tablet, you see another ad with new details about the guitar.