The system should always keep users informed about what is going on, through appropriate feedback within reasonable time.

On the Internet, it's survival of the easiest.... Give users a good experience and they're apt to turn into frequent and loyal customers. But ... it's easy to turn to another supplier in the face of even a minor hiccup. Only if a site is extremely easy to use will anybody bother staying around.

People have to want to change before there's any chance of helping them do so.

Even better than good error messages is a careful design which prevents a problem from occurring in the first place. Either eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action.

Clear content, simple navigation and answers to customer questions have the biggest impact on business value. Advanced technology matters much less.

If your users have many questions, it's a failure of your primary site design. It becomes not so much customer support, as much as customer complaints.

Minimize the user's memory load by making objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate.