You know that little “Do you want to send a read receipt?” message you get every now and then when you open an email? You might reasonably assume that if you don’t see that message, you’re not sending anything back. That’s not necessarily true. Thanks to the magic of something called a tracking pixel (a tiny image embedded in HTML and/or JavaScript), just opening the email can tell the sender not only when you did it, but your IP address (and, therefore, your location), email client, and operating system. Tracking pixels have been around for quite a… Read more