THE Secret of GMAIL Timer

Hey every one of use who use GMAIL had noticed a timer at side of every mail but do you know the secret behind that.

My friend G Praveen Kumar had explained all this.It was really interesting to know that Gmail’s timer is simply awesome.
I also haven’t noticed how it works.
Actually When ever we receive or send a mail we get the information about time when the mail was received or sent as shown:

7:04 AM (7 hours ago)

Do you know what it means ?

Just check here for all your answers here.