What is Google’s Supplemental Results?
When you do a search, you may some some results show as Supplemental Results in Green Letters. These are the pages which which are added to supplemental index. If your web page is in supplemental index the chances of getting listed is very less, but are there are chances, if the number of results are too small.
Why does Google put these pages into supplemental Index?
1. It could be a copy of another website or a webpage.
2. I could be a blank page or a page without much contents
3. It could be a page which does not have a incoming link or a orphaned page
How can we change a supplemental page to a regular page?
1. You should change the content and the best will be to change the URL itself and submit a sitemap to Google
2. If its a empty page, add sufficient content
3. If its a orphanged page, create links to that page and wait for Googlebot to crawl.
My Experience
I had some pages which were in supplemental index. I could really not understand why was that. I checked those pages well and I was sure that those pages were unique. I did not wanted to any of the above mentioned things as it was not a copy page or empty page nor an orphaned page. I just waited for few weeks, All those pages came to main index. The supplemental results tag was no longer there. From this we can understand that we need patience and give sufficient time to Google.
