Media Type Axis (show axis)
The T-MUM was built based on previous research. The T-MUM utilizes the media types from the literature to maintain consistency. The media types, listed by increasing complexity, are:

• text,
• sound,
• graphics,
• motion (this includes both animation and video), and
• multimedia.
  (Heller & Martin, 1999)

Interactive Expression Axis (show axis)
The T-MUM also utilizes the interactive media expressions from the literature to represent levels of functionality; those levels are:

• passive,
• reactive,
• proactive, and
• directive.
  (Aleem, 1997, 1998)

Contextual Expression Axis (show axis)
Next, the T-MUM has its own media expressions to explain how each media type is used contextually. The contextual expressions, along with an explanation about each, are shown below by increasing pertinence to the end user.

Discordant
Intrusive/Disruptive - The discordant classification typically serves a purpose outside the interests of the user. For example, a Web ad banner or any advertisement that is for a product or service not related to the topic of the artifact would be discordant. A media element might also fall into this classification when a novice developer fortuitously includes an element that detracts from the user experience.

Innocuous
Insignificant/Trivial - The innocuous classification typically serves an aesthetic purpose. At most, it is intended to evoke an emotional response. A picture of a flower added to someone's personal Web site simply to look pretty could fall into the innocuous classification. From the user's perspective, elements falling into the innocuous classification do not particularly add or detract from their experience.

Augmentative
Adjunct/Additive (in a minimal way) - The augmentative classification typically serves an additive purpose. Augmentative media types offer related information or offer support of some type. Additionally, an augmentative media element may develop its relevance within the context of the application in which it is used: for example, a sound effect that occurs each time the mouse is clicked; the sound becomes a notification to the user that the system recognizes their selection.

Relevant
Related/Supporting - The relevant classification serves a supportive purpose. Relevant media types offer purposeful information, but are not the primary source. The relevant media element might offer either redundant or secondary information - related, but not necessarily vital to convey the purpose of the multimedia artifact - or surface relevance to its purpose. An example is a sound effect of a thunderclap when reading about tropical storms.

Requisite
Vital/Required - The requisite classification serves an informative purpose. The information is of structural relevance to the intended purpose of the multimedia artifact. A Web site's navigational structure, a list of available courses and their descriptions on a university's site, or an instructional video would all be classified as requisite.

Examples of T-MUM in use are available as well as a 'T-MUM Tutorial' interactive presentation.