This paper provides a qualitative investigation into the many ways in which exposition mediates exclusive knowledge about copyright and copyleft to lay-people and (semi-)experts with different profiles, needs and goals, in different user situations. The analysis moves from objective exposition in the copyright article of the Oxford Dictionary of Law, primarily intended for inclusion and knowledge transfer, to institutional and non-institutional webpages at the front end of Google search listings (pages from GOV.uk, Techopedia, MakeUseOf, the GNU Project). While highly ranking online pages are generally held to be objective, credible and authoritative sources of knowledge, non-professional online dictionary articles may depart from lexicographic practice and provide thin if incorrect content (e.g. the Techopedia dictionary article). Moreover, the goals of self-promotion and persuasion may frame expository content, which may communicate the ideology shared by author and principal organization, and therefore take on a significant argumentative dimension (e.g. the GNU's page What is Copyleft). Another point concerns the ability to reach out to the lay-person in new genres and media: the analysis suggests that popularization strategies and usability principles interact in diverse ways and to different extents in (multitype) expository texts written for online communication, on pages which benefit from dilution of information and recourse to expandable content down or outside the sitemap.