Payments and Web Intents
From W3C Wiki
Web Intents provides a mechanism whereby the user can select which provider to pass to a web page requesting a given intent. This breaks free of the current practice of hard wiring the web page to specific providers. There are multiple solutions for Web-based payments, and users should be given the choice of selecting the means of payment that best suits them in the current situation. Web Intents has the further benefit of minimizing the information disclosed to the Web Application, which only sees the payment solution provider chosen by the user, and doesn't get to find out just which set of credit cards etc. the user has in her wallet.
Some measure of privacy is given by existing payment solutions where the Web application makes use of a third party to perform the secure payment transaction, and doesn't get to know the number of the credit card used (as an example). Web Intents improves on this by avoiding the need for Web applications to have a fixed connection to such third parties.
Open standards for Web payment APIs
Call for Implementations
To get the ball rolling, we need volunteers to work on experimental implementations that extend web browsers to support a variety of payment solutions via Web Intents.
Defining this as "intent" is a good idea. This might spur some ideas:
transaction promise 1USD endpromise promise 1 pack of gum endpromise endtransaction