Abstract: A system and method for conducting commerce over a distributed network manage merchant and product information in an electronic shopping basket, payment source information in an electronic wallet, and shipping address information in an electronic address book, all of such information being stored on a consumer computer. A commerce client running on the consumer computer is configured as a MIME handler and extends the functionality of a standard Web browser to support computer-based shopping. A merchant site Web server provides HTML-coded Web documents which describe merchant products and which host computer-based shopping options. The HTML-coded Web documents contain function-calling information by which consumer-selected options invoke shopping-related functions on either the merchant (server) computer or the consumer (client) computer.