Formatted emails with links look good and track a lot! To stop the tracking, set your email client to not download remote images/content or select the email client in text mode. It will change your reading experience, though.
Email marketing relies on “spy-pixels”, and modern email-based customer journey orchestration is built on these GIF or PNG files as small as 1×1 pixels and placed somewhere in the email. You literally won’t be able to see or even get to click on them.
It has been an accepted, if somewhat not fully understood, practice. Data protection regulations focus on consent, or lack of it is beginning to get noticed even in this practice.
As a sender, you have the option of requesting read/delivery receipts from the recipient. But they have the opportunity to deny it. This is where HTML, with its formatting options, helps remove this option or consent. Embedding images and stylesheets into the email becomes possible. They are downloaded when the user reads an email. Open rates, devices and even rough physical location is possible to be deduced and if the email has links then interest profiles are deduced as well.
So the question of consent comes into focus. Should the service provider ask for permission? Some are approaching it from a perspective of policy/compliance and while others are thinking about privacy-protecting experiences.