The prepaid card is a good idea. And I wonder whether it is always necessary to authorise individual payments. For something like newspaper articles, payments could be pooled and transferred en bloc via some kind clearing mechanism that doesn't require me to have an account with every magazine or website I read. The seller wouldn't even know who was paying and the clearing institution wouldn't know what exactly is being paid for.

The reason why nobody does it that way is probably that it's difficult to garantee settlement and the credit risk involved. But do we really need such a garantee in cases where no physical goods are delivered? Maybe it's enough if it works in 90 % of all cases. That's more than the rate of legally acquired software licenses today.