Search engines may make the assumption that pages not linked to, or buried within a web site's internal link structure, are less important, just as they assume that pages that are not linked well from external sources are less important than those that are. Linking from the home page to content that you would like to rank can improve that page's rankings, as well as linking to it from a sitemap and from various related content within the site. This models real-world human behaviour as well. Popular products are often prominently featured in the front of a stone.
One way to push pages down the link hierarchy is to implement pagination using "< prev" and "next >" links, without linking directly to the individual pages. Consider the example of the fourth page of an article that is split into four part. It is reached like this :
Home Page -> Article Part 1 -> Article Paart 2 -> Article Part 3 -> Article Part 4
The fourth page is harder to reach not only by humans (who need to click at least four times), but also by search engines, which could probably consider the content in that page as less important. We call the effect of this link structure "death by pagination", and we suggest two possible approach for mitigating the problem:
Don't use simple pagination. Page with "< prev" and "next >" links, but also add links to the individual pages, that is "< prev 1 2 3 4 next >". This creates a better navigation scheme to all pages.
