Email Detection

Sophisticated Email Marketers can detect whether you opened their email. After a mailing they review their list and see who opened their mail and who just threw it in the trash unopened.

How do they do that?

The key is the images. Magazine quality Emails contain images such as photos, buttons, and graphics. These images are not technically part of the email itself. Email is text only. The html text of the email has commands in it that tell the email program (Microsoft Outlook for example) to download and display images in the email. All email images exist in someone's web site. They are not in the email or email program at all. They are simply references to pictures that exist on the web.

To detect whether an email was opened you append the recipient's (your) email address to the image filename. When the email program requests images from the web, one of these requests includes your email address. They just record who is downloading images in their database. Conversely, if you throw the email in the trash without opening it, no images were downloaded, so your email was not recorded. They know you never opened their mail.

Email newsletter systems can tell if your email was bounced, was opened, and if you clicked through on any offers. All this email action that you thought was in the privacy of your computer is actually taking place on the server of the person that sent it, where they have computer programs set up to record your information. If you don't want to encourage them, don't open it and don't click through on any offers!