M

Mail bomb:
An orchestrated attempt to shut down an email server by sending more messages than it can handle in a short period of time. See DOS.

Mailing List:
A mailing list is a list to be sent specific mailings to.

Mail loop:
When automated responses or forward on mail servers result in an endless sequence of emails.

Mail Merge Personalisation:
Feature of the better email marketing tools that allows each email to each subscriber to be personalised based on information for that subscriber. When each email is sent out, a call to the database retrieves information like the actual first name of that subscriber and pastes it into the email. Important feature of the software for permission marketing and CRM.

Mailto:
A code to make an email address in either a text or HTML email immediately clickable. Clicking on the link opens the user's email client and inserts the email address in the "To".

Mail Transfer Agent (MTA):
A computer that forwards email from senders to recipients (or to relay sites) and stores incoming email.

Mail service provider (MSP):
Web based email service such as Hotmail, Gmail (google).

Multi-part mime:
Message format which includes both an HTML and a text-only version in the same message. Most email clients have full html facility. Clients may opt not to display html in order to avoid viruses.