Before the advent of portal technology, a large proportion of a new project budget would be spent on establishing infrastructure for delivery of business functionality.
Portal technology allows developers to concentrate on smaller
components that can be combined together in a composite manner to
allow users as well as IT analysts to create new systems.
This capability, to combine the smaller components, I believe is often overlooked, by a lot of project teams that focus on delivery of the functionality that is required to satisfy just the current functional requirements. The more a developer has to build in one component the higher the risk of delivery failure. Thats why composite systems, through focusing on building smaller components decreases the overall risk of total delivery failure.
A portal aggregates content and services from potentially many sources. This includes internally developed components. Imagine the possibilities of providing, through controlled means, access to these components to your key partners and customers. And vice-a-versa, gaining access to relevant, live and real time information from your partners. Then combining these into new components into applications without writing code. This is what a portal does.
Thus a portal can create new composite applications that can facilitate new business processes with out the need for costly projects or change requests.
So a composite system improves corporate agility through providing the means to assemble business processes from with in and outside the enterprise through exposed capabilities with a framework such as that provided by Portal technology.