From an Accenture article entitled Desktops of the Future:
The portal as a desktop provides a single view of the work, and gives members of a team a view of their workplace that has the potential to unite them, not make them feel cut off from one another and from their work. As portals evolve from being used primarily as communication and knowledge management tools to supporting the real-time performance of collaborative job tasks, they promise to provide a workspace dimension that is not only unified but also unifying. That is, they can enhance the feeling of connectedness that is vital to the culture of a company.
Properly designed and delivered, workspace portals provide a common area where ideas, information and resources can be exchanged and discussed. Through this open exchange, workers’ performance can be enhanced and better directed toward organizational goals.
An important but often overlooked point about portals is that the rhetoric about a “single point of entry” may oversimplify how difficult they are to integrate. In fact, a portal solution most often is a “federated” one: An enterprise portal may provide the common entry point for all users. But these users will then be passed through to their relevant workspace portal, which is focused on their particular performance needs.