As the scope of our information systems grows, they have to cope with increasing heterogeneity. When information comes from remote, autonomous sources, the control over consistency that is required to achieve effective production of information in traditional system is lost.
Heterogeneity exists at many levels.
Progress at the level of the infrastructure is being made. For instance, there are a number of adequate tools that bridge differences in hardware and operating systems, and today the person browsing the web is only occasionally aware of the underlying incompatibilities. However, many incompatibilities remain in the underlying data. More appropriately we would speak of having information starvation in a glut of messy and heterogeneous data. The objectives of research in mediation is to improve the integration of heterogeneous data is to provide aid with the search for relevant data, combine data derived from multiple heterogeneous sources, and process the result to create real information for the customer.