This architectural principle states that the shape of a building should be primarily based upon its intended purpose, or function. In idea making we should value this same principle, subsequently we need to resist the temptation to design around design rather than the mission of the idea.
I spent some time Tuesday night over at the Toms Shoes headquarters listening and learning, here are two TOMS axioms;
1. Keep the mission clear. TOMS exists to put shoes on childrens' feet. The design of the company forms around this clarity.
2. Allow the story to pull you forward. We have a tendency to get ahead of the story (or too far behind it) rather than listening and allowing it to lead. Scale your idea with the steps of success along the way.
So build exclusively around serving your the story of your mission and avoid making something cool that doesn't do much of anything at all...