"Development of information services (such as business applications, data warehouses, directory services etc) available across the organisation is preferred over the development of information silos which are only provided to a particular department or group of departments."
Duplication capability is expensive and propagates conflicting data.
It also militates against a policy of sustainability in the use of infrastructure resources such as servers and data centre air conditioning.
Business departments/functions will not be allowed to develop capabilities for their own use which are similar/duplication of enterprise-wide capabilities. In this way, expenditures of scarce resources to develop essentially the same capability in marginally different ways will be reduced.
Departments which depend on a capability which does not serve the entire enterprise must change over to the replacement enterprise-wide capability as soon as practically possible, if it is available.
The design of business service capabilities to replace silo applications will be driven directly by the business processes they are designed to support.