Google ranks all the websites out there based on popularity, visitor, importance and some other basis. This rank given by Google is known as page rank or PR. These PR starts with N/A and goes all the way up to 10. That means PR 10 is given to the best quality websites. Then it goes like PR 9, PR 8 and so on. When visitors start visiting website Google gives a PR of 0. Then with good content and increase in regular traffic for a whole 6/7 months will get your site a PR of 1. If visitors keep rising and website is upto the quality, after another 6/7 months you will get a PR 2. Google usually reviews PR in every 3 months and if the website is worthy of getting PR they update the PR instantly.
So thousands of website can have the same PR. Although, only a few website is having a PR of 10. twitter.com has PR 10.
A page having more PR is definitely having more value. Take for example, you have a website where you buy and sell products. If the website has more PR, may be the price is bit higher. The whole point of doing SEO is to increase visitors and the site moves among the top in search result, the main reason behind all these is to gain high PR.
There are several ways to check PR of your website. One of them is to visit www.prchecker.info. The easiest way is to use the add-ons named PageRank Stats that comes with Google chrome. After installing this addons, you will see a logo on the right top of your browser. After setting this up, you will be able to see the PR of the websites you visit.
There is no denying achieving PR point is the goal of all the websites. PR is the ultimate reward given by Google to show its value of each websites which also helps user to trust sites.