Summary : If we try to understand what work is actually in the knowledge economy, it appears that it's mainly about handling, gathering and organizing intangible objects to deliver a tangible result. Many tools are provided to give these objects a material existence on our screens to make their manipulation easier. At the end, a dual conclusion emerges : not only the skills that are necessary to this kind of work are seldom acquired or even taught but tools, as they exist today, make the situation getting even worse...