There are plenty advertising media companies that use tracking pixels common method for tracking email and knowing pretty much everything around your activity related to emails, your IP, browser information, the device you’re reading your current email even when you click something or not without you knowing.
If that worries you, it’s time to install UglyMail google chrome extension that warn you whenever your email contain tracking pixels. Simply & easy click link above, once installed you will see a tiny eye box right next to email subject.
Creator of plugin (Sonny Tulyaganov) confirms Uglymail does not store or save any of users’ data
Currently working with Google Chrome and Gmail, other browsers and mail services like yahoo mail, hotmail, Firefox and Safari should be expected soon.