As I mentioned, customers have the greatest success when they begin by building key features that add a lot of value quickly, and defer others. You gain the immediate feedback you need, and can continue the momentum to roll additional features to additional groups, until you have reached your business goal. Security is another key issue. Setting the appropriate levels of security so that you encourage sharing of information while maintaining access control is key to success. In addition, this is the time begin your communication program so users become aware of the portal and begin to understand how they will use it.
People tend to resist change, even when it is for good reasons and delivers tangible benefits.
Keep in mind that your target audience is already getting information, collaborating, and communicating using other methods your goal is to change how they interact. To do that, you need to have a plan to help them. We have a customer acceptance program to help users change their behavior and accelerate usage of the portal. We follow a standard process of configuring, testing, and deploying the application to the target audience. This is the optimal time to train system administrators, followed by end-user training.