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.

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

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.

Inadequate use of usability engineering methods in software development projects have been estimated to cost the US economy about $30 billion per year in lost productivity.

A bad website is like a grumpy salesperson.

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.

Users spend most of their time on other sites. This means that users prefer your site to work the same way as all the other sites they already know.