Usability
Architecture = 80% of usability. - If users can't find what they want in 3 clicks, you've lost them. It's critical to build an effective navigational structure. In addition to this users have gradually become accustomed to particular layouts and phrases on the Internet.
There are numerous conventions such as using the term 'Home' for organisation information, the terms 'Shopping cart' and 'Check Out', the organisations logo top left with a link back to the home page.
As the Internet matures users are become increasingly used to things being a certain way. Breaking conventions can damage web usability.
User task flow - match page flow with user workflow.
KISS - Keep it simple - Make controls obvious and understandable.
Avoid confusion between emblems, banners, and buttons.
