Why organize based on electronic gear?
Category Descriptions for Electronics
These categories have been organized in a way that allows the performer to view quickly the amount of technical expertise necessary. One can immediately see additional amount of gear, time and dedication for any solo in the shortest amount of time, access the score, and return to the practice room.
The initial basis for categorization is the number of output channels: Two Channel vs. Multi-Channel. Once again, I’m thinking of the performer and the benefits mentioned above. These lie at the top of “the pyramid” in my mind. The other “categories” are to me, a bit more like “mediums” of composition using different gear to make art. While this genre was evolving, these two categories were some of the most ubiquitous lending themselves to the history and leading to the 
introduction of newer technology and other categories.
So to continue, Interactive Systems refer to input & output requiring a computer and ample equipment. Examples of equipment implementations include microphone input(s), Foot pedal controllers and other forms of interactivity. (I.E. Microsoft Kinect,
MIDI Controllers, Microphones and typically special software like Max, Pd, Sound Collider, etc).
While Video implies the use of simply a projector in various formats for visual media output and typically 2 standard audio output, the MIDI Percussion category implies MIDI Input by a popular modern digital instrument. The Grab Bag speaks for itself with ideas of “guitar pedals” of delay, chorus, or any other unique combination.
The following is a simple list of the above.
Two Channel – works that use only a 2 Channel Playback System. Most pieces are with “tape,” “CD,” or “fixed media.” Simply “press play” utilizing minimal equipment.
Multi-Channel – works that utilize 3 or more channels of audio output only.
• Click Track implies 3 Channels as a standard (L/R output + 1 channel “click”)
• Others include quadraphonic output, or larger again refers to larger setup size.
Video – works which include a video output component; a projector will be necessary including a screen for display. Flash video, QuickTime are some examples of the file formats.
MIDI Percussion – works that include the use of a MIDI Controller such as a DrumKAT, MalletKAT, Handsonic, “triggers,” or the equivalent. A computer, sound module or “synthesizing source” may be necessary in addition to the instrument.
Interactive Systems – works that employ the use of microphones (input), computers & software that has created an interactive-music system in order to process audio or play electronic accompaniment via “triggers” aka MIDI. Such software types include MAX/MSP, SoundCollider, Pd, Kyma, Kinect devices and others.
Grab Bag – works which defy categorization or yet to be created. These works may use of a contact microphone, “guitar” effects foot pedals such as delay, chorus, reverb, etc. A great category regarding works for mobile phone.