It’s important to understand that page rank does not compute relevancy, only the importance of each page. When a user makes a search query, a different algorithm calculates the relevancy of page, while page rank simply selects the most important result.
http://www.seochat.com/c/a/Search-Engine-Optimization-Help/Page-Rank-Optimization/
SERP Monopolies are likely to become very common within the next 3-5 years.
