I would actually submit that their has been no true micro-payments service other than some credit systems (e.g. XBox Marketplace). Is there a place to sell documents, audio, or video for 5 to 10 cents a piece and getting 60 - 80%? I believe the paper from 2003 is not a predictor of what would happen in Amazon or Apple would have such a system. Both have excellent UI and easy process in buying higher priced media.