The Challenge for Change (known as Societe nouvelle in French) program was developed, at the Trudeau government's request, by the National Film Board in the late 1960s. The program's primary goal involved using documentary film and, especially, documentary video, to effect social change within the country. Started in 1967, Challenge for Change, in my opinion, reached its peak in 1970 with the creation of the film "VTR Rosedale," a work which epitomises the way in which the program changed the form of documentary filmmaking.
In creating "VTR Rosedale," (the VTR stands for Video Tape Recorder) the Challenge for Change documentarists subverted the traditional power structure of documentary film, in which the director (or whoever's holding the camera) is positioned as an outside observer who records the subject's actions. This approach had, until Challenge for Change, been the primary method of documentary film, from the first documentaries such as "Nanook of the North" (dir. Robert J. Flaherty) until the 1960s. This structure, of course, privileges the director's biases and personal views, if not reinforcing the sort of mythical idea that documentary films are in any way objective. The organisers of Challenge for Change, on the other hand, saw their role as that of an intermediary: they wanted to put the reins, so to speak, of the documentary into the hands of those who were being documented.
This approach to filmmaking, although it can be seen in earlier projects such as that on Fogo Island (off the coast of Newfoundland, is most fully realised in "VTR Rosedale." To create this film, the Challenge for Change organisers instructed the inhabitants of the mining community of Rosedale, Alberta in the use of VTR portapaks (sort of a precursor to camcorders) and editing equipment, hoping that this technological "medium empowerment" would lead to social empowerment. Rather than being documented by an outside observer, the people of Rosedale would be able to document themselves. The film "VTR Rosedale," then, documents the instructional process as well as showing the documentary made by the people of Rosedale.
The two major reasons for the rise of Challenge for Change were, firstly, the social liberalism of the Trudeau government and, perhaps more importantly, the first development of cheap, portable video-recording equipment. It's easy to forget, in this era of four-hundred-dollar DV camcorders that, until the 1960s, moving-image technology was more or less entirely restricted to the media elite (Hollywood, newscasters, government film agencies). These new video recorders were also relatively uncomplicated to use: this, combined with the relatively low price and ease-of-use of video tape (as opposed to film), meant that VTR portapaks were the perfect instrument for this new form of documentary.
Prevailing wisdom says that Challenge for Change failed in its efforts. This is partially true: firstly, the films created by the program did not effect any demonstrable social change (although "social empowerment" is difficult, if not impossible, to quantify). Secondly, while Challenge for Change claimed that they were not patronising towards the subjects of their films, in is hard to escape the feeling that they positioned themselves as dei ex machina or as the gods of a cargo cult, bringing miraculous new technology to the isolated, impoverished communities to which they journeyed. Still, what Challenge for Change did succeed in was the exposure of the power structure on which traditional documentaries are based. This exposure has profoundly affected the ways in which modern-day documentaries are conceived of and approached, and, for this if nothing else, Challenge for Change should be applauded.
For more on Challenge for Change and video documentary in general, look for "Video: The Changing World", ed. Nancy Thede and Alain Ambrosi, which I haven't actually read but I hear is really good. | 
