PageRank is Google’s system for ranking web pages. A page with a higher PageRank is deemed more important and is more likely to be listed on a page with a lower PageRank.
Google describes PageRank:
PageRank relies on the uniquely democratic nature of the web by using its vast link structure as an indicator of an individual page’s value. In essence, Google interprets a link from page A to page B as a vote, by page A, for page B. But, Google looks at more than the sheer volume of votes, or links a page receives; it also analyzes the page that casts the vote. Votes cast by pages that are themselves “important” weigh more heavily and help to make other pages [...]
PageRank (also known as PR) is a rating system from 1 to 10 used by google for every page on the internet – the higher your website’s PageRank the better. You can check your blogs PageRank by using this tool. http://www.prchecker.info/check_page_rank.php
PageRank does not go up in equal steps, for instance, PR2 is double a PR1, PR3 Is double a PR2 and so on, so going up from a PageRank of 1 to 2 isn’t hard, but going from a PageRank 5 to 6 is a huge task (as the below bar chart shows)
To give you an idea of general PageRank here is a small list of sites and their PRGoogle and Facebook PR10 Youtube and Twitter PR9 Asos and Ebay.co.uk PR6 Boohoo.com [...]