MIME (Multi-Purpose Internet Mail Extensions)
MIME (Multi-Purpose Internet Mail Extensions) is an extension of the original Internet email protocol - SMTP (Simple Mail Transport Protocol). MIME lets people exchange different kinds of files like audio, video, images, applications, and more, as well as the ASCII text used in the original protocol. In 1991, Nathan Borenstein proposed that SMTP be extended. He proposed to the IETF that internet clients and servers would be able to handle other kinds of data than ASCII text. As a result, new file types were added to "mail" as a supported internet protocol file type.
Servers insert the MIME header at the beginning of web transmissions. Clients use this header to select an appropriate "player" application for the type of data the header indicates. Some of these players are built into the web client or browser (for example, all browsers come with GIF and JPEG image players as well as the ability to handle HTML files); other players may need to be downloaded.
New MIME data types are registered with the Internet Assigned Numbers Authority (IANA).
MIME is specified in detail in Internet Request for Comments 1521 and 1522, which amend the original mail protocol specification, RFC 821 (the Simple Mail Transport Protocol) and the ASCII messaging header, RFC 822.
Rouse, M. (2005, September). MIME (Multi-Purpose Internet Mail Extensions). Retrieved February 18, 2013, from http://searchsoa.techtarget.com/definition/MIME