Strike - Share your experience and hold businesses accountable 👊
ReadNotify - ReadNotify enables the user to know when email is sent and the reciever reads the email.
dip - accountability groups for developers
GetNotify - GetNotify is a free email tracking software solution.
Rainmaker - Rainmaker allows you to make your Google Contacts better.
WhoReadMe - WhoReadMe is an email tracking solution that provides details on read duration, recipient location, organization name, operating system etc.