link: https://mashable.com/article/how-to-block-email-pixel-tracking/

Here’s something you might want to think about next time you check your email: chances are, at least some of your messages are being tracked.

From how many times you open a message, the time of day, and even what city you’re in, the very act of reading an email can send a surprising amount of data back to the sender, even if you never respond.