Traditional system development starts with abstract system specifications and ends with interface design. To Jason Fried, this is backwards.
"Functional specifications documents lead to an illusion of agreement. A bunch of people agreeing on paragraphs of text is not real agreement. Everyone is reading the same thing, but they're often thinking something different. This inevitably comes out in the future when it's too late."
Instead we should start from the user interface and build out from there.
"...the interface is the functional spec. First with some quick and simple paper sketches, then directly into HTML. Unlike paragraphs of text that are open to alternate interpretations, interface designs are common ground."
- The article Getting Real, Step 1: No Functional Spec
- February 15, 2005 - via UI Designer
See also: Prototyping and wireframing (32)