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This is technically not a website issue as it is about emails. (Emails and websites are two different technologies that do different jobs. But, in most cases, they are closely linked. Apart from anything else an organisation has a website called www.widgets.com and email addresses that are xyz@widgets.com so most people will think emails are part of websites.) But the exploitation of a website’s potential is linked to the best use of emails and that is maximised by the use of an auto-responder.
Autoresponders are programmes that deal with non-personal incoming mail. They also send out automated emails in many different situations.
(Because we use advanced website techniques we'll know from which page your question comes.)
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