Why does'nt google index all the pages of a website. It shows some of the pages as supplemental results.

Well, google has to type of indexes one is main and another is supplemental....google rank webpages on basis of content and relevancy factors and the better pages index in main index and others go to supplementals. However after a little time supplemental pages may also shift to main index...recently the syntax to find supplemental results has been changed and you can not find supplemental results by searching -

site:yourdomain.com in google search box.

how to find supplement results now information please visit at Webexcel Forums where i got this information

Supplemental results are a warning about duplicate content on your site. You can check those results by entering in the syntax [site:www. domain.com ***] in Google search box.

To get your pages out of them, you need to make sure that every page on your site has unique content and provides excellent and relevant information, has a unique title and a unique meta description. Also make sure that every page of content has only one URL that can access it