Abstract: A multiple entity purchase and sale transaction system enables shoppers and sellers to conduct business on internet using shopping groups. Group shopping allows sellers to sell goods and services to groups of shoppers at low prices. The multiple entity purchase and sale transaction system can be implemented as a group shopping web site. The group shopping web site allows unrelated shoppers to create, join, and check out a shopping group during open enrollment period. Sellers are allowed to provide bids to a shopping group during the open enrollment period of the shopping group. At the end of open enrollment period, a group shopping administrator selects an accepted seller. Finally the group shopping web site links shoppers in the shopping group and the accepted seller together so that shoppers can pay the accepted seller for goods and services and the accepted seller can provide goods and services to shoppers.

Abstract: A global email classification system enables email messages to be classified based on various factors into many categories. The global email classification system includes email classification servers, email classification clients, and other components. Personal email messages are in a special category. This invention includes a method to classify email messages into personal email messages and non-personal email messages. In an email classification system, an email message is processed by the email sender classification client before it is sent out. The email sender classification client requests a challenge object from the email classification server. The challenge/response process plus other factors determines the email classification. The challenge/response result is stored in the email classification server as an email data object.