Email tracker apps

OBTrack

OBTrack is an extension for Google Chrome and Opera.It tracks your email for free without any "Sent With" branding.It not only let you know who read it but also informs you about when, where and how many times it was read. It has got better privacy policy as it does not read your emails nor ask permission to send emails on your behalf.It is a very useful tool for people who use emails extensively.