Net concrète might be a way to describe the work of artists who sample the greater sludgepile of internet content. Using the wikipedia-simple definition of musique concrète as practiced by Pierre Schaffer and applying it to the art of the surf club artists (a breed that becomes logy and sluggish after a spatiotemporal environmental event known as "graduation," but here goes anyway):
1) [Schaffer] developed the concept of including any and all sounds in the musical vocabulary. At first he concentrated on working with sounds other than those produced by traditional musical instruments, removing them from their original context. Later on, he found it was possible to remove the familiarity of musical instrument sounds and abstract them further by techniques such as removing the attack of the recorded sound.
2) He was among the first to manipulate recorded sound in the way that it could be used in conjunction with other such sounds in the making of a musical piece. This could be thought of as a precursor to contemporary sampling practices.
3) Furthermore, he emphasized the importance of play (in his terms, jeu) in the creation of music. Schaeffer's idea of jeu comes from the French verb jouer, which carries the same double meaning as the English verb play: 'to enjoy oneself by interacting with one's surroundings', as well as 'to operate a musical instrument'. This notion is the core of musique concrète.
Keep these criteria in mind and look at this page of examples culled by Marcin Ramocki from the Nasty Nets blog. While it's true that each post has a specific and sometimes quite literal satiric intent there is a sense of randomness of a quasi-oceanic environment being dipped into and splashed about. The difficulty of trying to explain this art to the dry, very dry, resentful people who hang around the Rhizome chatboards is they can't hear the music. They expended much effort to prove that all this quotation had been a function of Net Art all along and there was "nothing new here." But the sampling of Nasty Nets, et al wasn't just for analytical or statistical purposes, there was an invisible tune everyone was riffing on. Fortunately some people got that.