Here’s a workable definition of Culture Jamming from Wikipedia, the free encyclopedia -JS
Culture jamming is the act of transforming existing mass media to produce commentary about itself, using the original medium’s communication method. It is a form of public activism which is generally in opposition to commercialism, and the vectors of corporate image. The aim of culture jamming is to create a contrast between corporate or mass media images and the realities or perceived negative side of the corporation or media. This is done symbolically, with the “detournement” of pop iconography.
It is based on the idea that advertising is little more than propaganda for established interests, and that there is a lack of an available means for alternative expression in industrialized nations. Proponents see culture jamming as a resistance movement to the hegemony of popular culture, based on the ideas of “guerrilla communication”.
Culture jamming’s intent differs from that of artistic appropriation (which is done for art’s sake) and vandalism (where destruction or defacement is the primary goal), although its results are not always so easily distinguishable. See the rest at Wikipedia…