I have come across two wonderful services which lets you track emails you send and be notified when, where (city/country) and how (desktop/mobile) the email was read.
Spypig service comes in handy if you want to track your email and want to know exactly when your email was read. It can also give you information such as receiver’s location, ip address and application used to read the mail.
SpyPig is a free email tracking tool that notifies you as soon as your recipient opens your email message. SpyPig is dedicated to all those paranoid individuals out there who can’t stand wondering all day if their VIE (Very Important Email) has been read or not.