The absence may be disciplinary. I know that Shane Greenstein in his discussions of internet adoption takes up the very prominent role that pornography distributors have. In diffusion of technology terms, pornography has been major content source for VHS and DVD media as well as internet and broadband adoption. I believe there is quantitative data there, I don't have a reference at my fingertips though. Best regards, John Laprise, Ph.D. Assistant Professor of Communication in Residence Northwestern University in Qatar Northwestern University