Ask HN: Any examples of a proper website plan/spec. document?

Ideas fly through the tech community in droves. Many startups were born/died because of great/poor website planning and design. I have yet to see a smart document that effectively describes a website plan to both the designers and then the programmers (who may or may not be founders or employees). It's clearly quite important in the case of SAAS or web apps.

Does anyone have any samples of GOOD QUALITY documents which can guide personnel through this critical task? With so much frank and open dialog these days, perhaps someone has seen a good example posted in a blog post which I missed?