There are steps you should take to counter the effects of the supplemental index :
- Ensure that the navigation of your site is even. If the structure of your site is like a tree, with the directories being the branches and the pages the leaves, your tree should look symmetrical, rather than lopsided, if you want the life-giving sap of PageRank to pass evenly down through to each and every page.
- Try to ensure that at least 10–15% of all the inbound links to your site are “deep links” to important internal content or category pages.
- Test pages on your site that might be too similar to one another using tools like the Similar Page Checker at www.webconfs.com/ similar-page-checker.php. If the page pairs fail the test (or you
have a strong suspicion they may already be in the supplemental index), consider rewriting them from scratch and giving them different URLs (without using 301 redirects). This should get you a fresh start.
- Make sure that the URLs do not contain too many parameters and that the size of each page is less than
How Google stores the index
Know how google works can help webmaster to understand how to improved website.
The supplemental index
The number of pages appearing in the supplemental index increased substantially.
How to check the supplemental index?
There are some simple step to find out which of your pages are in the supplemental index.