usability.
The purpose of your website is to generate sales. It is imperative that your customers are able to easily navigate your website and make the purchases for which your website was designed.
Interaction
How well is your customer retaining and understanding the information found on your website?
If your website is not easily comprehended or retained, or not properly marketed to your targeted segment, then you are missing important website usability. The 3 or 4 most important pieces of information your audience seeks should receive the most attention and should be featured most prominently on your homepage. Give your visitors the information they want immediately, before they lose patience and visit a competitor.
Don't make your visitor work to find your offerings. Your mission should be clearly stated on your homepage and a first-time visitor should be able to understand it within less than 30 seconds. Keeping your information simple, concise and easy to understand is critical for effective usability.