Send Email Through Gmail And Track It.

Some times we send email to any person and wish that receiver see this email urgent. Because we dont know that receiver see email or not. When receiver send us answer let we know that he/she read our email.
Microsoft outlook provide some features about this problem, then we send email from outlook we add option that we send reciept to receiver but its receiver choice that was accept or reject read receipt.
 For this problem a great solution RIGHT IN BOX its available web extension for google chrome, mozilla firefox and safari. After installation this extension a new button was appeared on gmail which is called TRACK.