Although information systems are essential tools enabling companies to make the most of their resources when faced with excess information, it is frequently only fair to observe that they are ineffective. From our point of view the principal problem is one of organisation and conception. In a project of this type, a company often spends longer on the production phase than on the conception phase. This is a deep mistake which prevents the system from adapting to new trends and makes it less flexible. To build such a system on solid foundations, it is desirable to spend more time measuring the field it must cover and the precise manner in which it is to be used. This thinking period is important, as all existing systems must eventually be given a new dimension. Simultaneously, conception studies must be underpinned by a global, coherent and simple vision providing a sense of purpose for the whole. Finally, the implementation must be the fruit of a rigourous approach, built around four essential key points : - creating or building up a common language for the entire marketing and sales department, - being very vigilant to ensure proper balance between the different users, while attempting to provide the same level of service for all, - implementing a test phase, limited but full sized, - appointing a genuine head of information and system management. All these small items are necessary to ensure this major project results in a system that is durable, correctly managed and generally able to cope with excess information.