Reverse auction services, namely, allowing registered buyers to post via a global computer network purchasing requirements by line item in either an open or private auction format, while concomitantly allowing registered vendors the opportunity to bid to provide those goods and services via a global computer network; automated and computerized trading services; on-line trading services, including allowing registered users to provide evaluative feedback on one another following transactions; computerized searching, ordering and on-line purchasing, trading and sale services; providing access to on-line directories, indices and searchable databases relating to a variety of information and data available on a global computer network, including information regarding credit worthiness of registered users; dissemination of advertising for others via an on-line electronic communications network; providing an on-line searchable database for the sale of goods and services of others; providing an on-line searchable ordering guide for locating, organizing and presenting goods and services of others; database aggregation, integration and management services; on-line trading services