Reply to post:

I see nothing wrong with a mixed system. Ad-free sites can offer themselves as subscription-only sites, and free sites can retain the adverts. I pay a subscription for a good Usenet service, and I'd also pay for several sites that I use regularly, and PPV for a few sites I use infrequently. The average site could have very low subscription fees (< £1 per month) and still get plenty enough income to maintain the site.