Make it accessible All vendors should get the same set of rules when working with your artwork, and it needs to be accessible. The homepage of styleguide gives the most relevant information up front by providing quicklinks to important information and a printable version.
Brand Rules The purpose of the guide is to make rules about how to use the logo, acceptible color combinations, typefaces that support the image, and so on.
Stationary Templates The guide provides all the artwork for download, for you're printer or designer to use. Some of those templates include logo, letterhead, business card, envelope, email, spreadsheets, fax cover sheet, labels and even CD labels.