PageRank is 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. We have always taken a pragmatic approach to help improve search quality and create useful products, and our technology uses the collective intelligence of the web to determine a page's importance.
from: google.com
Hmm.. Do you know there is free tools to check and monitor your PageRank easily and also can let you know, estimates the value of your website..
yeah.. it still beta.. but there is nothing to lose if you want to try it.. hihiihi.... here is the link... http://www.smartpagerank.com/