Intertextuality and collaborative authorship sounds all very fine to us postmodern folk, but to students, it is far from a philosophical matter.
Rebecca Moore Howard describes the ways in which students are frequently subjected to the most chilling penalties for practices that Hull and Rose describe more charitably as "patchwriting," an apprenticeship process rather than an intellectual crime.
My own most unnerving brush with this phenomenon came when I attempted to work with the Department of Psychology on a Writing Across the Curriculum project. Undergraduate Psychology students were asked to write summaries of short texts "in their own words." Several who used some of the words of the original were hauled on the carpet by the Psychology department, not for failing to follow instructions but for intellectual dishonesty. No efforts by other members of the research team could convince the Psychology people (a) that this was not plagiarism, or (b) that using some words from the original is a good way to write a summary.
Howard suggests that academic institutions must develop much clearer codes that "account for the contingent nature of authorship" (798) and spell out in detail the various lines that can be crossed between patchwriting, non-attribution and downright cheating. Trying to remedy excessive legalism by spelling out legalism more exactly may strike one as trying to put out a fire with kerosine. However, at least it does not assume that students will automatically know that practices which they cannot distinguish from what we call "research" are in fact viewed with horror by academics.