Websites that are effective are sites that stick to a theme. Designers who ignore this basic rule are prone to creating sites that contain a potpourri of works. Novices who create personal sites often fall into this type of designer. They create sections covering their favorite music, resume, photos, diary, and more. It might be somewhat acceptable for personal sites, but professional sites that do the same are often passed over.
Without getting into a long discussion over globalization and competition under such a huge competitive market, it's safe to say that a site theme is something worth obeying. Users find sites with themes to be palatable. Even common sense would indicate someone who is looking to learn about the intricacies of The United States Constitution would probably not try to find such information on a site that contained a huge treaty on Newton's Laws of Thermodynamics.
Lynch & Horton (2001) recommend linking internal pages back to the homepage. To maintain a theme, doing so through the use of familiar logos and graphics makes a theme more pronounced. The same would be true for the overall layout, in that colors and style revolve around a site template.