A method for doing business, wherein a web server maintains a commercial subscriber database including a plurality of records each containing data relating to commercial subscribers including at least name, address and category, and imposes a periodic subscription fee on at least some of the commercial subscribers. On receiving from a client machine connected thereto a request to download data relating to at least one specified category of commercial subscriber, it extracts from the commercial subscriber database respective records and sends to the client machine for display thereby, allows receipt of an update from one or more commercial subscribers in respect of substitute or supplementary data to that contained in the respective database record of the commercial subscribers, and updates the commercial subscriber database as required.