What is supplemental result?
A supplemental result is a page stored and retrieved from the supplemental index of Google rather than from the main index of it. While Google puts what it thinks is good wine in the main index vault and serve them most of the time, those from the supplemental index rarely receive much attention from searchers. As a webmaster, though one cannot avoid being indexed as supplemental results, he should reduce the number of supplemental results of his site as small as possible.
To do this, one should bear in mind the following advice:
- Write originally.
- Build lengthy pages filled with concrete content.
- Never use dynamic URLs with parameters for content pages.
- Distinguish your page and describe the content in title tags and HTML headings.
- Keep the body of every page unique, avoid content duplications insite.
- Update old pages every once in a while. Google knows and appreciates it.
For more information, please refer to What is wrong with Supplemental result