Secure methods of payment are needed before we will see widespread commercial use of the Internet. Recently proposed and implemented payment methods follow one of three models: electronic currency, creditdebit, and securecredit cardtransactions. Such payment services have different strengths and weaknesses with respect to the requirements of of security, reliability, scalability, anonymity, acceptability, customer base, flexibility, convertibility, efficiency, ease of integration with applications, and ease of use. NetCheque isapayment system based on the credit-debit model. NetCheque is described and its strengths with respect to these requirements are discussed.

This thesis presents a new architecture for information discovery based on a hierarchy of content routers that provide both browsing and search services to end users. Content routers catalog information servers, which may in turn be other content routers. The resulting hierarchy of content routers and leaf servers provides a rich set of services to end users for locating information, including query refinement and query routing. Query refinement helps a user improve a query fragment to describe the user's interests more precisely. Once a query has been refined and describes a manageable result set, query routing automatically forwards the query to relevant servers. These services make use of succinct descriptions of server contents called content labels. A unique contribution of this research is the demonstration of a scalable discovery architecture based on a hierarchical approach to routing.