Computers are tools that help people accomplish tasks by making the process easier, faster, cheaper, less error-prone, or just more fun.
But what tasks? And by what process? What parts of the process can the computer make better? How can users interact with the computer to make it do its part of the process? Only lastly can we ask: what must be presented to the user and how?
Video: http://vimeo.com/45897174/