Customer Support and Mailing Lists
Do you use a company email address for mailing lists? many people do. Probably because firewalls prevent them from using their personal mail address. Unfortunately many corporate emails have autoresponders to tightly integrated with them.
When you post to the php general mailing list for example, you invariably get at least one message from some company's autoresponder saying they will get back to you immidiately. Some of them also thank you for contacting them.
This kind of mails tells you two things