Peter and I have had this conversation many times and I’m glad he’s written down his views on the relationship between print and the web for publications:
Still, the flaw in the print person’s perspective is in thinking that there is any relation between your print audience and your web audience. There is none. You are not undercutting your print product by publishing a website because the people who you can reach online have almost no overlap with the people who you reach in print. Your print readers don’t want your website, and your web audience doesn’t. want. your. paper. (or magazine). (There’s a small overlap for whom that’s not true — many of whom are the mediavores who read articles like this one.) Audiences are more stratified by media habits than they are united by common interests.
I don’t totally understand the last bit (italics are his), but the rest rings very true for me. (Just to give some context/credentials: Peter worked in research for print publications for many years, so there’s some rigor to his analysis.)