Google is a Map Maker

Most Web site operators have a fundamental misconception about Google. They think that it is all about their content. Wrong! Google is just as much interested in what your pages connect to than in what they contain.

To be crawable, a webpage must take you someplace else. No page exists in isolation from other pages. There always should be some type of topical hierarchy that a given page will fit into.

Certainly as a minimum every webpage should take you to its home page. It should also connect you to its parent page. As well as to its children. If your webpage has been Wikified than it will, also, link to important topics that are mentioned on your page.

A SEO should always think in terms of hierarchy of topics. The highest level topic would always be that of your home page. Each different directory of your Web site should discuss only one primary topic. Under that primary topic will be one or more subtopics. At that level each webpage should be devoted to exploring just one topic.

In Google, linking to other pages is considered the sign of a quality webpage. And, improves the overall importance of each page. But, just about the worst thing that any webpage can do is present Google with an unexpected dead-end. Too many many dead-ends on a Web site will greatly diminish the crawlability rating of your site. And, may even result in webpages landing in the supplemental index. Crawlability has absolutely nothing to do with W3C Validation.

To be crawlable a webpage must take you someplace else. And, should not contain any unexpected dead-ends.