Designers are not users.

To design an easy-to-use interface, pay attention to what users do, not what they say. Self-reported claims are unreliable, as are user speculations about future behavior.

Ultimately, users visit your website for its content. Everything else is just the backdrop.

Windows '98 is so similar to Windows '95 because Apple hasn't invented anything worth copying since 1995.

Consistency is one of the most powerful usability principles: when things always behave the same, users don't have to worry about what will happen. Instead, they know what will happen based on earlier experience.

Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Any such information should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large.

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