SpyPig is a free email tracking system which can send you a notification when your friends read your email. SpyPig is a simple email tracking system that sends you a notification email as soon as the recipient opens and reads your message. It works with virtually all modern email programs: Outlook, Eudora, Yahoo Mail, Gmail, Hotmail, AOL Email and many others.
Both you and the recipient must use an HTML email, not plain-text or rich-text email. Visit the Requirements & Limitations page to learn more about SpyPig limitations and basic requirements.
To use SpyPig, simply provide them your email address, then type your message title (this is for better tracking so that you can know which email has been read). You can then choose your SpyPig image (if you don’t want your recipients know you are tracking the email, choose a blank image). After that, you can paste the tracking image on your email message and then send out the email.
SpyPig - Free Email Tracking System