The Verge: Everything You Need To Know About The Invisible E-Mail Tool That Tracks You

The Verge: Everything You Need To Know About The Invisible E-Mail Tool That Tracks You. “You know how every image on the internet is stored on a server, and your computer automatically downloads them as you browse? Years ago, some genius figured out that your computer’s image requests can let those same servers track your activity across the web — and when it comes to email, they can let the sender see when you’ve opened a given message just by sneaking in an image.”