ReadNotify - ReadNotify enables the user to know when email is sent and the reciever reads the email.
GetNotify - GetNotify is a free email tracking software solution.
Bananatag - Find out what happens to your emails after you press send! Add email tracking, attachment tracking, email scheduling and templates to your daily emails.
EmailTrackerPro - EmailTrackerPro is an email tracking and spam filter solution.
Poppulo Email Communications - Poppulo provides a complete internal communication tool. Create & send better employee emails, measure results with IC specific analytics. Get a free trial.
Intelliverse Email Tracker - Intelliverse Email Tracker provides insights to increase the productivity of your emails.