Google Supplemental Index
Google's Supplemental Index, is a secondary database containing Supplemental Results – pages deemed to be of less importance by Google’s algorithm or are less trusted.
The primary measure of a pages importance is the number and quality of links pointing to that page. Pages in the Supplemental Index can still rank in search results, but this will depend on the number of pages in the main index relevant to the search.
Some reasons pages may be in the Google Supplemental Index
- Duplicate content
- Low PageRank
- Lack of trust
- A site with a large number of pages
- Page freshness
- Excessively long URLs
As of July 2007 Google discontinued the practice of placing a “Supplemental Result” tag on search results making it near impossible to tell whether a result is in the supplemental index or the main one.
