Criterias to decide website Usability

Determing Target Users:

1. Focusing on users who already access website to improve satisfaction.
2. Target new users
3. target Search Engines,Advertiserrs

Focussing on design elements:
1. Are animation/graphics hindering user?
2. Page layout impacting performance?
3. Can usability improved by changing navigation structure?

Focussing on usage patterns:

1. Studying user behaviour
2. Determining time user spend on page.
3. Response time of website:Time user get to retrieve information/place an order.

Focussing on Site styles:
1. Focussing on branding?
2. Is cross-site navigation a critical variable?

Source: http://www.sigchi.org/chi97/proceedings/sig/jms.htm?searchterm=website+usability