What do I think Détournement is? From the sounds of it, it is reusing and adapting older pieces of art, whatever form that may take, into a newer form in order to speak a modern message, using that older piece. I could be wrong, but that is what it sounds like. Taking something that already exists, that people know and recognize, and adapting it to say something you want it to say in oder to bring that message to the attention of people. Sounds like a great concept; its both functional and productive, and easier than other forms to do.
Or I just misread it....