Modding is the act of adapting hardware/software to have it do what you want it to do, which does not always correlate with what it is originally built to do. Biomodd(ding) is inserting a living ecosystem inside a computer system, varying from plants that grow and develop with the use of the waste heat of the computer to algae that function to cool a processor; "living cooling liquid". In an almost symbiosis-like state nature and machine living together. Even though it, of what I've seen so far, ends up being quite interesting sculpture-like installations, the main importance is that they're meant to be actually used.
In one set-up in the Phillipines they developed a multi-player game and used this structure as the server. Which resulted in: "social meeting getting translated through a sequence of events into biological growth and development." And this is where the different levels appear; Biomodd is about the game-element, it is about the social aspect and it is about the biological aspect. And it is really cool to look at, have a look for yourself: