Online merchandising system, online catalog presenting method, server, computer program product, and computer data signal

The shopping server provides an online shopping service with retrieving information of items handled, relations among the items, user's purchase history, user's request, and the like via the internet or the intrafirm network. The shopping server generates electronic catalogs personalized for each user based on the retrieved information so as to show useful and helpful information to each user. The catalogs are categorized in accordance with the purposes. Some of the categories are fulfilled by the automatic entry in accordance with the item relations or the user's purchase through the online shopping service, while the others are fulfilled by the user's arbitrary designation. The shopping server presents the generated catalogs to the users via the internet, so that the categories are switchable and customizable by the user.