Basically a page rank is created by working on the important pages of your website and how many times that page is visited by the users and what all kind of links you provide to that page. Page rank is actually judged by the number of incoming links on the page. Page rank is basically a value given to that web page.
Page rank is displayed as a green bar to the left of the webpage in the Google directory. The basic factor behind page rank is the keyword. If your keywords are rare and unique then your page rank doesn’t matter and if your keywords are in the competition the page rank becomes an important part as that you have to compete with the rest of the sites that use the similar type of keywords.
There are two types of page rank:
First is the rank which sits in the algorithm on the Google. And the second is the visible page rank which is what we can see in the browsers on the toolbar or by using a widget in your browser.
The visible page rank is not updated oftenly for rankings and is just a snapshot. Suppose you have a page rank of 4 which were made few months ago but the now Google has stopped updating the ranks oftenly and the ranks are updated within a period of long time. Google says that the visible page rank is now updated only a couple of times a year.
But most of the people are focused on their website rank which is probably not an issue. If your page rank has dropped but the customers have risen up then page rank does not matter in that case. The page rank does not matter a lot the page owners because if there sales are rising up and the rank is not good then who cares about the page rank of that web page.