If on-site algorithms look at the relationship of words and content on a page, then whole-site algorithms look at the relationship of pages on a site. For example, does the home page content relate to the content on other pages? This is an important factor from a user’s viewpoint, because if users come to your site expecting one thing and then click through a link and wind up in completely unrelated territory, they won’t be happy. To ensure that your web site is what it claims to be, the whole-site algorithm looks at the relationship of site elements, such as the architecture of pages, the use of anchor text, and how the pages on your site are linked together. This is one reason why it’s best to have separate web sites if you have a site that covers multiple, unrelated topics or subjects. How your site is architected — that is, how usable it is for a site visitor, based on the topic it appears to be about — is a determining factor in how useful web site visitors find your site. Understand that one of the most important concepts in SEO is how useful site visitors find your web site, and a recurring theme throughout this book is building sites that visitors want to spend time on. Do that and SEO will (usually) fall naturally into place.

Off-site algorithms
I can hear you already. ‘‘What does anything that’s off my web site have to do with how my web page ranks in SERPs?’’ The answer is incoming links, which constitute an off-site factor that will affect your page ranking in sometimes dramatic ways. A good incoming link is the equivalent of a vote of confidence for your site, and a high level of confidence from surfers will also help boost your page ranking.
Notice the emphasis I placed on good incoming link? That’s another of those vitally important things you should commit to memory. Good incoming links are those that users willingly provide because they found your site, or a page on your site, useful. These typically are not links that are paid for.
Let’s go back to the concept that creating a site visitors will find useful is your best SEO tool. Good incoming links are how visitors show other visitors (and therefore web crawlers) the value they attach to your site. The number of good incoming links you have is directly proportionate to the amount of confidence and trust that visitors appear to have in your site.

In summary, the off-site algorithm adds yet another dimension to how the quality of your page is ranked. Like the other algorithms, it’s not a stand-alone measurement, but a component of a larger algorithm that tries to extract the true value of the web page or web site.