Once the most important part of Google’s ranking system, but now one of hundreds of search engine algorithms, PageRank is an important part of search engine optimization (SEO) past and present history. PageRank is a link analysis algorithm applied by Google.com that assigns a number or rank to each hyperlinked web page within the World Wide Web. The basic purpose of PageRank is to list web pages from the most important to the least important, reflecting on a search engine results page when a keyword search occurs. The basic process involves PageRank evaluating all of the links to a particular web page. If a web page has a lot of links from large websites that also rank well, then the original web page is given a high ranking. Where the links are coming from is just as important as the number of links to any particular web page, the system being rather “democratic” according to Google.com.
PageRank was developed at Stanford University in 1995, in order to create an algorithm for Google that would allow the website to rank all web pages based on merit and not on Meta Tags because of the spamdexing abuse and other unscrupulous actions. The mechanics of PageRank measures how likely it is for a visitor to reach a particular web page through random clicking of other websites, whether they are related extensively or just for one or two keyword phrases. Higher ranking in PageRank equates to a greater probability of the site being reached because they are not only quantitatively linked to a number of times, but are also linked to other popular web pages.
PageRank has a number of different uses now that it is just one of hundreds of algorithms that Google.com employs to rank web pages. The Google Toolbar has a version of PageRank that features a smaller version of the algorithm. Visitors with the Google Toolbar can stop on a web page, and the toolbar will display a PageRank of 0 to 10 for the page, 0 being an obscure page and 10 a highly visible page. This type of ranking is not the careful form that Google uses to rank pages on search engine result pages, but gives a visitor some idea of the popularity of a page. The Google Toolbar PageRank is generally a tool that allows people to see the visibility of a page they may want to link to without performing in-depth research.
There are companies that “link farm” or build business solely on the manipulation of PageRank results. The links from well-ranking pages of PageRank are sold to companies seeking other SEO methods. Google.com has warned companies that participation in link farming will result in the links being discredited and the rankings lowered. This threat has not discouraged some companies who continue to abuse PageRank.