"Clearing house for rights holders" refers to copyrights. The payment system used for copyright licensing is irrelevant since the business is dwarfed by other transaction costs. I doubt Google and Yahoo! will be able to compete even with retailers like iTunes or [various sites that, per _Grokster_, I do not intend for any readers of this to use], much less clearing houses.

The Harry Fox Agency (http://www.harryfox.com/index.jsp) is a long established copyrights clearinghouse. They are used to licensing in very big chunks. So are newer clearing houses such as Orchard. (http://www.theorchard.com/thedeal/index.php).

Levchin's comment that PayPal is really providing "risk management" rather than just a payment system is another instance of the importance of transaction risks. The mechanics of the payment system are an irrelevant fraction of an EBay transaction's costs. And as Levchin points out the nature of transaction risks are different for different kinds of sales.

Both the seller and the buyer have to worry about transaction risks, and these worries limit the granularity of payment systems. For a look at this from the buyer's point of view -- the risks of not getting the value you thought your were paying for -- see
http://szabo.best.vwh.net/micropayments.html

> The blinded signature patent of Prof. David Chaum expires: [see at bottom]

I agree --- this is a historic date.

I'm not a big fan of untraceable digital cash.... I'm not sure Ian is either. But the Chaum patent is not totally untraceable. It is intended to be *sufficiently* untraceable. Perhaps too untraceable perhaps not, depending on your politics.

Everybody involved in the design of money systems should study the Chaum invention both for the technical features it employs, and to consider where you stand on the goals and outcomes you think are desirable.

The rewards await you, once you understand how cryptographic algorithms can be implemented to bring about to mask particular elements of information from particular parties in multiparty arrangements while strongly nailing down other elements. The rewards of course are envisioning how various combinations of algorithms can be used to achieve design requirements for other purposes. Another that comes to mind are voting systems that ensure against fraud, ensure the necessary kind of auditability of elections while preserving the requirement of a secret ballot. http://www.google.com/search?q=votehere+algorithm+open