Visual Communication and Web Application Design

In order for a Web application to be "usable", it must be understandable. It needs to communicate, and communicate effectively. When a user interacts with a Web application they have only the visual presentation (the interface) to "tell" them what the application has to offer, and how they can make use of it. As a result, designers must rely on visual communication principles to tell our audience: about the behavior, structure, and purpose of our Web applications. The better at communicating we are, the easier it is for our audience to understand our messages and intentions, and the easier it is for them to use and appreciate our Web applications.

Wroblewski, Luke. Functioning Form (2005). Articles>Web Design>Usability>Visual Rhetoric