Mail server
A computer in a network providing post office facilities. It stores incoming mail for distribution to users and forwards outgoing mail through the appropriate channel. The term may also be used to refer to e-commerce software or Shopping Carts that performs this service which resides on a machine with other services.

Message Integrity
The communication sent is the same as the communication received.

Metadata
Information about data. Metadata describes how and when a particular set of data was collected, by whom it was collected and how it is formatted.

Metatag
Information about a website which is attached to the website usually in HTML. Metatags are not seen by web viewers but help a search engine to categorise a website. Inappropriate words or descriptions in metatags are sometimes used by website creator owners to direct internet traffic to their site. In some situations this may amount to a breach of the Trade Practices Act 1974 (Cth)

Multipurpose Internet Mail Extensions (MIME)
This is a specification that can format non-text data or non-ASCII messages, such as graphics, audio and fax, so that they can be sent over the Internet. Many web browsers and e-mails providers support MIME.