Check out this post on the Google blog. Google will no longer be labeling results in their index as being “supplemental,” and they offer some nuanced language suggesting the line between sites in their supplemental index and their main index will diminish.
There has been an outcry from webmasters begging Google to reverse course. For many, the supplemental label is a tip that problems exist and must be addressed.
Watch It On Demand: Advanced Marketing Guide to Online Retail 2015