Why SOA; when surely it’s easier to start with a clean sheet?

A question often asked is ‘What’s the value is of leveraging existing business applications for reuse in Service Oriented Architectures (SOA), when surely it’s easier to start with a clean sheet?’
Existing business applications are among the most valuable assets a company owns because they support business critical processes and information which impacts every aspect of the relationships the business has with its customers, partners and colleagues. Put simply, existing business applications are the functional DNA of the enterprise.
The advantages of reusing these applications (which are already tried and tested) are significantly lower risk, lower cost and less development time.
Does this mean that the business does not have to change its existing application portfolios? Well the answer is ‘maybe not’ but ‘maybe yes’ because it is vitally important that reuse is based on the best functional elements drawn from the portfolio and integrated successfully in order to deliver the required implementation of business services.
SOA-enabled business application modernization approaches identify asset reuse and gaps so that the technical implementation roadmap for an SOA can be defined. For example, where duplicated functions and processes exist across different business areas, which is best one to use?
Getting to ‘smart’ SOA is all about meeting the challenge of integrating existing applications. For more information see