Architectural Concerns When Selecting an In-House Integration Strategy - Experiences from Industry

Consider the scenario where two or more software systems have been developed in-house, for different purposes. Over time, the systems have been evolved to contain more functionality, until a point where there is some overlap in functionality and purpose. The same situation occurs, only more drastically, as a result of company acquisitions and mergers. A new system combining the functionality of the existing systems would improve the situation both from an economical and maintenance point of view, and from the point of view of users, marketing and customers.