An auto-responder e-mail is an e-mail which is sent back automatically to everybody who sends an email to a mailbox with this feature enabled. The senders will receive the automatic reply the moment their e-mails are received and you'll not need to a single thing by hand. A few instances of taking advantage of auto-responder emails are mailing a validation that a payment is received and the order will be processed or that an individual is on a break and will not be available for a specific time period. In the first situation the function is enabled permanently, whilst in the second one it is non permanent. Even though you use an e-mail exclusively for private communication, you may use an auto-responder to let the sender know that the email has been received successfully.