Google doesn’t look kindly upon attempts to game its PageRank system. Google PageRank is the way Google determines what order to display search results. The higher a page’s rank is, the higher up the page appears in a search results list.
According to Google:
PageRank performs an objective measurement of the importance of web pages by solving an equation of more than 500 million variables and 2 billion terms. Instead of counting direct links, PageRank interprets a link from Page A to Page B as a vote for Page B by Page A. PageRank then assesses a page’s importance by the number of votes it receives.
PageRank also considers the importance of each page that casts a vote, as votes from some pages are considered to have greater value, thus giving the linked page greater value. Important pages receive a higher PageRank and appear at the top of the search results. Google’s technology uses the collective intelligence of the web to determine a page’s importance. There is no human involvement or manipulation of results, which is why users have come to trust Google as a source of objective information untainted by paid placement.
What happens when a website tries to game Google’s PageRank system? Philipp Lenssen has an interesting post about one such case over at Google Blogoscoped: