PageRank is a proprietary algorithm developed by Google to determine the usefulness of an individual web page. Ranking scores from 0-9, where 0 being the lowest and 9 being the highest rank.

Characteristics / Implications

The algorithm of PageRank is constantly changing to better reflect the usefulness of each web page. There are approximately 200 factors used to determined the PageRank score of each web page.

You can find out the PageRank of any webpage through the use of Google Toolbar.

Background Information

Before Google was created, Yahoo and other search engines index web pages manually -- i.e. if you have a website and if you wish your website to be listed in Yahoo, you will have to submit the web address (URL) to Yahoo, and Yahoo will send someone to take a look at your web page and manually abstract crucial information from your site and list them on their search engine database. In the later years Yahoo and many other major search engines implemented a paid advertisement scheme that lists sponsored listings higher in the search results.

These strategies Yahoo and other major search engines back then adopted, however rendered the search results in a way that favor the commercial results instead of informational result, thus largely lowered the usefulness of the search results. Larry Page, founder of Google, hence developed the PageRank mechanism to determine a page's usefulness and created Google base on such mechanism.

Search Engine Marketing Value

In this digital world flooded with information, there are all kinds of alternative content regarding a single subject, though only the useful ones will be considered worth and legit to quote and reference (linked). This is also why PageRank has such a tremendous success helping Google to filter out less useful pages from their search result. It is very likely that all major search engines will adopt similar algorithm in ranking their search results, thus it is very important to rank good under Google's rules to maximize the sustainability and ROI of the Search Engine Optimization (SEO) and Search Engine Marketing (SEM) effort.