Natural anchor text distribution is crucial today, because of the anchor text filters used by search engines.
How do you describe what natural is.  A natural link looks like as if it was built by a user, not someone who has optimised a website (SEO).  Normal users don’t care about anchor texts and so if all your links look like built by an SEO you are deep in trouble!

This time it is all about search engines and the measuring of links.

PageRank and Links as Votes:

The initial idea behind Google’s legendary PageRank system was that a link to a particular page is equivalent to a vote by the linking page for the linked-to page. By measuring the keywords and their relevance on a particular page and also the number of “votes” or links it had, Google could determine which pages were considered by the web’s users to be most valuable for the given search terms. On top of this, links from web pages that already had a high PageRank would be more valuable than links from low PageRank pages.

Search engine optimisation (SEO) is the process of improving the volume or quality of traffic to a web site from search engines via “natural” or un-paid (“organic” or “algorithmic”) as opposed to search engine marketing(SEM) which deals with paid inclusion. Typically, the earlier (or higher) a site appears in the search results list, the more visitors it will receive from the search engine. SEO may target different kinds of search, including image search, local search, video search and industry-specific vertical search engines. This gives a web site web presence. One aspect of SEO is link building.