An online catalogue is a listing of items or products available for purchase presented on the Internet.  In e-Commerce, the ability to browse through products online and select from amongst alternatives is key to enabling simplified transactions.  The supplier can control and update the description, unit of purchase/unit of sale, and price, and prospective buyers can access the information prior to selecting the product that they want.  Catalogues can either be maintained by the buyer’s organisation or by the supplier, and can link the master data about the product into both the seller’s systems and the buyer’s systems.  Simplifying the transactional purchasing process, so that end users can ‘self-serve’ and choose what they want from selected suppliers at pre-agreed terms can help change the role of procurement from processing individual transactions to managing the overall category or contract.  See also e-Commerce and e-Marketplace.