The core requirements for every user interface are that they must be intuitive and maintain a high level of usability.

To be intuitive, the different parts of an interface must be structured in a way that make it easy to understand, the layout of elements on pages must be consistent and recognizable, while functionality must be presented in a way that anticipates how a typical Internet user would go about using the application.

Usability, according to Nielsen (2003) is defined by five quality components:

* Learnability: How easy is it for users to accomplish basic tasks the first time they encounter the design?
* Efficiency: Once users have learned the design, how quickly can they perform tasks?
* Memorability: When users return to the design after a period of not using it, how easily can they reestablish proficiency?
* Errors: How many errors do users make, how severe are these errors, and how easily can they recover from the errors?
* Satisfaction: How pleasant is it to use the design?