Art whose material is software itself: code, programs and interfaces. The term took hold around 2001 with festivals such as transmediale and the Runme.org repository.
Texas Instruments Germany actually reached out to Herbert Franke and they asked if he could put an interactive software art piece on every single home computer that Texas Instruments distributed in Germany.
thefunnyguys, One Year of Le Random
We have a lot of examples of software media art which is about interaction, which is about protocols. And you can make really easily the case there is a history of protocols already used in software art.
Paul Seidler, terra0 on the Autonomous Forest