Misinterpretations of Google's Page Rank Score

Few concepts dealing with SEO (search engine optimization) are misinterpreted as often as Google's page rank score. 

The easiest way to see the displayed page rank is to install a SEO plugin to the Firefox browser.  Page rank as most recently released by Google is displayed on a bar in whole digit increments.

One fairly accurate way of thinking of page rank is to consider it a rating of authority of a particular page determined by the Google search algorithm, perhaps with input from human reviewers.  The visible scores range from a low of zero to a high of ten.  However, the real (intermediate, unreleased) scores might include decimal places.

In fact, all pages have some page rank, so even though no page rank is shown for a given page, that doesn't mean that the page's rank is zero, only that it is less than one half. 

One common misperception of page rank is that it is a direct predictor of where a page will rank in the search engine listing for searches.  Often people are surprised to find, for example, a PR 2 site displayed ahead of a PR 6 site in the results. 

There ought to be no surprise in such a result--at least not for any people who truly understand how search engines work.  Just because a page is recognized as an authority, that does not mean that the page is an authority on the specific subject that the searcher has queried.  A scholar's research report on the subject of string theory may be recognized as an authority, but it is not going to show up for a search for a meatloaf recipe, because the page's authority status is not relevant to the query.

A second, particularly careless, misperception is that page rank somehow denotes that the entire site is more valuable or important.  I often receive solicitations for reciprocal linking claiming that I will receive an external link from a PR 5 site.  I do not respond.  There is no such thing as a PR5 site.  Pages are assigned rank; websites are not.

Page rank is an important consideration in obtaining an external link, but only the page rank of the page on which the link actually appears is pertinent.  Consequently, it is usually better to receive a link from a PR3 page than a PR1 page that happens to be on a site that has a PR5 home page.

Other than where your external links are placed, page rank is a mostly irrelevant factor for businesses.  Clearly, a higher page rank is better than a lower page rank, but it is much more efficient to concern yourself with the factors that directly impact SEO on your site and the basic external optimization efforts.