The mail tracker extension by 500apps, named openedornot, enables users to monitor email behavior through the use of a tracking pixel. When the recipient opens the email, the pixel activates, collecting data about the recipient. This technique provides insights into email engagement.

1. Mail Tracker Extension | OpenedOrNot by 500apps
Email tracking is a technique for monitoring the behaviour of an email message, typically with the
aid of a tracking pixel. When the email is opened, the pixel or beacon is turned on and data
regarding the email receiver is gathered.