An architecture style guide is a document that explains how the site is organized, why it is organized that way, and how the architecture should be extended as the site grows. The guide should begin with documentation of the mission and vision for the site. It's important to understand the original goals of the site. Continue with information about the intended audiences. Who was the site designed for? What assumptions were made about their information needs? Then, follow up with a description of the content policy. What types of content will and won't be included and why? This documentation of lessons learned and decisions made during the research phase is very important. These underlying philosophies drove the design of the architecture. Any future modifications to the architecture should be determined by this early work. Also, if the goals change or the assumptions prove incorrect, corresponding architectural modifications may be required.