A case study is presented of creative collaboration using new technologies, comprising (i) socio-technical history of the design, implementation and diffusion of a multimedia software programming language, and (ii) analysis of the structures of participation of diverse actors in the continuing development of that language across a range of current creative practices. The language is Max/MSP, initially developed for interactive music performance in the late 1980s, and since broadened to become a sort of lingua franca for a global software community engaged in interactive multimedia installation and performance. Max grew out of a confluence of researchers on live electronic music composition and performance in the 1980s, working first at IRCAM, a large European center for computer music research, then shifting in its commercialization phase to small U.S. based companies initially catering to academic music departments, and then independent artists. The ecology of the Max community is finely differentiated, with four distinct niches that will be specified in this paper based on interviews and surveys of designers and users (core system, external object, instrument, patch). A key dimension of this analysis is concerned with ownership, circulation, and sharing of contributions made at these different levels, and in diverse socio-cultural environments; for instance, one dialect of this language remains partially proprietary, though with a vigorous practice of free sharing at the instrument and patch level. In the phrase of one of the original developers, the ecology of Max exhibits a "hierarchy of incompleteness", which will be elaborated as a useful theoretical construct in contrast to the apparently idealized 'flatness' of subsequent collaboration environments. Programming audio-visual flows requires future events to be scheduled and synched with other events, a complex technical operation that is well supported in patchwork-style technical environments pioneered by Max. Unlike formal, text-based logics, the patchwork is graphically specified, and operates by hooking-up one functional object with another, while permitting the artist-user who is not a technical specialist to observe the sensorial consequences of changing such connections in real time.