SpyPig - Free Email Tracking Service

SpyPig is a fully green gadget that does not require registration, installation, etc., and anyone who enters the website can use it for free immediately. When sending emails, you just need to paste the icon provided by SpyPig and send it together. Once the recipient opens and reads it, SpyPig will immediately send this information to your email. Currently, SpyPig already supports most mail programs such as Outlook, Eudora, Yahoo!, Gmail, Hotmail and more.