Note: Coordinating your information architecture, interaction design, visual design, and usability objectives into a long-term scalable deployment strategy presents numerous advantages. See "Ongoing Operations" section.
The web is the ultimate customer empowering medium. If the customer cannot find or use something on your site all the competitors in the world are but a mouseclick away.
In traditional physical product development, customers did not get to experience the usability of the product until after they had already bought and paid for it. On the web, people experience usability first and decide about where to purchase later.
There is only one book you need to read about Usability: Jakob Nielsen's "Designing Web Usability". There you will find all the basic usability analysis criteria that you will ever need.
Caution: usability myopia does not work.
It is impossible to apply all the usability rules at once without retreating back to the stone age in terms of information architecture, interaction design, visual design, and web marketing techniques. (Jakob Nielsen's web site is a great example).
You must advocate the use of common sense of when it makes sense to apply the rules, bend them, or disregard them completely.
Usability is not the only thing:
Have you ever bought a car based on usability alone?
Has the design of a product or how it made you feel ever influence one of your purchasing decisions?
Similarly to the human brain, in web presence development there
must be balance between the logical and the emotional.
You must understand your users, understand what tasks they need to perform, and design the interactivity and visual elements of your web presence accordingly.
Common mistakes:
Business model: treating the web as a marcom brochure rather than leveraging it as the ultimate marketing and efficiency tool.
Project management: managing a web project as if it were a traditional corporate project. This leads to an internally focused design with an inconsistent user interface.
Information architecture: structuring the site to mirror the way the company is structured. Instead, the site should be structured to mirror the users' tasks and their views of the information space.
Content authoring: writing in the same linear style you have always written. Instead force yourself to write in the new style that is optimized for on-line readers who frequently scan text and who need very short pages with secondary information relegated to supporting pages.
Note: Coordinating your information architecture, interaction design,