Google introduced tags to allow spreading of content across multiple pages without getting penalised. Useful if you have say multiple entries in a category that would logically be on the same page but you want on physically separate pages.
is it a new google search algorithm? even i want to know more about it. does any one have information on that?
Check out the Google Webmaster Central Blog and look for an introductory video called Pagination SEO by Maile Ohye. It's well produced and informative and will tell you all you need to be introduced to the subject.Hope that helps.
Have you still not learnt how to use Google Search? The first result is from Google: http://googlewebmastercentral.blogspot.co.uk/2012/03/video-about-pagination-with-relnext-and.html Or are you just a waste of time spammer?