When asking a question to a customer service or applying for something by email, (potential) customers often receive an email back to say that their request has been well received and will treated as soon as possible.
That’s nice: at least the customer knows that his request got through and that it will be answered as soon as possible. However, in this instant society customers like to know exactly when their question will be treated. So instead of saying ‘as soon as possible’ you might want to say ‘within 24 hours’ (if you can live up to that promise).
Another issue with automatic confirmation emails is that often the ‘sender’ of the mail can not be reached.