You all know about the Telephone answering machine.It is very helpful when you are not in home.In the same way if your email responds after receiving an email that you have got the mail.
Or suppose you are not in home,will be at home after 4days but someone sent an email.And your email replies automatically that you are not in home or any preloaded message like answering m/c.If anyone needs to contact you urgently then after reading your message he will contact you by other medium ( like-Mobile phone ).
It is possible in Gmail as well as in Yahoo !Today i am going to tell you how to setup an email answering m/c.It is fully free of cost without any kind of software or hardware.
For Gmail
Step 1 :
First log into your gmail account.
And Click on "Settings" at the top right side [ In Standard Gmail view ] or click on " Settings " [ In basic HTML view] at the top-right side of the page.
Email Answering Machine Setup
Step 2 :
In " General " tab ,there is an option " Vacation responder ".
Click on " Vacation responder on "
Step 3 :
Now write subject in the subject box.And also write the message in the message box.
now click on " Save Changes ".
Now when you receive a mail,automatically a reply mail will be sent to the sender.

For Yahoo!
Step 1 :
Log into your Yahoo account
Click on the settings button at the top right of the page.

Yahoo! answering m/c Setup steps

Step 2 :
Then click on " Mail Options ".
Now in Options Tab click on " Vacation Response ". 
Step 3 :
Tick on " Enable auto-response during these dates(inclusive) ".
Step 4 :
Just enter dates.Write your message .Click " Save "

That's all.You are done.
Now when you received an email,an automatic reply will be sent.