PageRank is used by Google to decide the placement on Search Engine results page (however, the importance of PageRank, now, is being questioned by experts). PageRank was the system on which google was developed. It has been named after a co-founder of google, Larry Page.
PageRank worked on the theory that a link to a page was a “vote” for the page. The more “votes” it had, the higher it was placed in Google. Links to a page or inbound links were called “backlinks” by Google and for a large time determined PageRank.
Even the text within the hyperlink was taken into account to decide how relevant a page was to a certain topic.
PageRank ranks pages from 1 to 10, where 10 is the highest PR a page can get. Pages can also have PR 0. The PageRank of a page can be viewed with the Google toolbar.
The number of backlinks to a page can also be seeb by using the following format:
link:http://www.URL.com
But Google does not display an accurate number of backlinks. Yahoo is much more reliable, and will always show more backlinks. It is believed that Google showed only backlinks from pages of PR4 or more, but recently lower PR links have been seen.
Google also takes into account the number of links on the page being ranked.
Each link to a page “passes” on a part of it’s PR, and that’s how a page gets it’s PR. It is believed 85% of the PR of a page/No. of outbound links on the page passing the PR is passed on to the page. Even internal links are used in the total number of outbound links, so a lot of links are required to get a decent PR.
A PR5 is worth about 4-6 times more than a PR4 (it’s actually believed to be around 5.5 but Google doesn’t say)
These are only assumptions. Google doesn’t disclose any information but has released it’s original PageRank algorithm to the public. Google hasn’t given any information about it’s “proprietary algorithm”. Besides PR, Keyword Density also plays a role in SERPs. Search Engines are getting smarter by the minute, and now have come up with some very innovative ideas for SERPs. Even the size and location of a keyword matters. A keyword within the heading 1 element (h1) on the top of a page has a lot more value than a keyword in a sea of text. Due to such innovations, people have come to question the importance of PR, but it still does play an important role.
PR of some known pages:
www.google.com – 10
www.microsoft.com – 10
www.karanmisra.com – 4
gudiblog.blogspot.com – 3
www.exunclan.com – 3
www.exunclan.com/logexun – 2
The PR of a page can differ from the PR of the parent site, as can be seen above.