When the email is opened, code within the pixel sends the info back to the company’s server. How does it work? A single tracking pixel is embedded in the email, usually (but not always) hidden within an image or a link. They’re also tracking whether you’ve opened the email, when you opened it, and where you were at the time by using software like Mailchimp to embed tracking software into the message. All of those obnoxious marketing emails that crowd your inbox aren’t just pushing a product.