towards a definition

I have made a simple model in my paper-in-progress trying to revise distinctions between personal media and mass media. I mentioned Luhmann's definition of mass media in my last post - I mentioned it because it really eloquently puts how we have usually understood mass media: as institutions in society that make use of copying technologies to disseminate [generally accessible] communication. Luca's comment to my last post is however important: to Luhmann mass media are a differentiated function system. Personal media are not, but are used within all of societies social systems. Trying to keep my blog-postings brief, I am sometimes too short (I may have a general problem of assuming people understand what I mean...). I believe my point is that definitions of mass media should focus exactly on mass media being institutionalised and professionalised. I am not particularly fond of Luhmann though. Which might be because I find him so utterly difficult. I like John Thompson however. His definition of mass media is not too different from Luhmann's: Thompson defines mass media through five typical characteristics: technical and institutional means of production and diffusion; the commodification of symbolic forms; a structured break between production and reception of symbolic forms; the extended availability of symbolic forms in time and space; and finally, mass media products are available in principle to a plurality of recipients (Thompson 1995: The media and modernity: page 27-30). Less than ever, these characteristics describe mass media only. This is why I rather focus on two axes: 1) Symmetrical relations/Mediated interaction <--> Asymmetrical/Mediated quasi-interaction. 2) De-institutionalised/de-professionalised <--> Institutional/professional. Personal media are non-institutional and non-professional and they are more or less symmetrical facilitating mediated social interaction.