E-mail tracking pixel & privacy concerns

E-mail tracking pixels are used to track various information from the recipient of an e-mail. Whenever you open an e-mail that contains a tracking pixel (most if not all of the e-mails contain tracking pixels especially marketing ones) you share a lot of information with the sender even though you don’t even know about it. This technique is more than ten years old and is used in similar way into websites for tracking purposes.

So what is a tracking pixel and how does it work?

A tracking pixel is a transparent tiny image (1px). Similar to an image of a website, whenever you see an image of a website with your web browser it gets downloaded locally to your computer. By downloading an image from a website you create new log entries in the webserver that contain your information. The same way works in the e-mail. When a pixel is embedded into an e-mail, just by opening and reading the e-mail you download that tiny invisible image. Some of the information you reveal to your sender:

Your IP address

Time/date of opening the email

How many times you opened the email

Your email client software

Your operating system

This is a big privacy concern as none of the senders let know you about the information they collect while you read the email.

Imagine someone asking you “why did you reply to my e-mail a week after your read it for 3 times”!!!