The world is too large and filled with too many diverse people and organisations for any single marketing mix to satisfy everyone. Unless the product or service is an item such as an unbranded, descriptivelabel, universally-required detergent aimed at the mass market, any attempt to satisfy everyone may be doomed to failure. An organis­ ation that decides to operate in some market - whether consumer, industrial, reseller or government - recognises that it normally cannot equally serve all the customers in that market. The customers may be too numerous, widely-scattered and heterogeneous in their buying requirements. Thus, organisations often need to identify the most attractive parts of the market, those they are best suited to serve or that section where competition is weaker or non-existent.