Working Backwards
By Amazon
Amazon's approach to product development is known as "Working Backwards". All projects work backwards from the ideal customer end state. This usually starts with a mock press release announcing the finished product. The press release is targeted at the end customer and contains information about the problem, how current solutions are failing, and why the new product will solve this problem.
The Amazon product press release is intended to be a gut-check for whether or not the product is worth building. If the team is not excited about reading it then document needs to be revised or perhaps the idea should be revisited altogether. As the team begins development the press release serves as a guide for the team to reflect on and compare with what is being built.