Communities and individuals often differ not so much in their values as in the priorities they set among values. In most writing which is neither creative nor academic, plagiarism is scarcely an issue at all. Broadly, this is because any unfairness in the advantage to be gained by text reuse is agreed by the community to be outweighed by improved speed, precision and efficiency of communication. This chapter investigates the factors that make plagiarism an important issue or otherwise in different circumstances and to provide evidence that we are currently concerned about student plagiarism because of the forms of assessment and associated educational ideologies we currently use. Educational systems in which plagiarism is irrelevant, and mimicry of research conventions in educational genres is unnecessary, can exist, although they are probably less than optimal. Less intensive grading within continuous assessment would allow plagiaristic practices where students found them useful or necessary, and hand responsibility for learning from writing back to students.