The End of Google's Supplemental Results
I was checking the number of indexed pages on a site today and i noticed that none of the pages were labeled supplemental. I did some sleuthing and found this thread on DigitalPoint Forums that linked to this Google Blog post that announced the end of the supplemental results.
Since 2006, we've completely overhauled the system that crawls and indexes supplemental results. The current system provides deeper and more continuous indexing. Additionally, we are indexing URLs with more parameters and are continuing to place fewer restrictions on the sites we crawl. As a result, Supplemental Results are fresher and more comprehensive than ever. We're also working towards showing more Supplemental Results by ensuring that every query is able to search the supplemental index, and expect to roll this out over the course of the summer.
In a nutshell, they have stopped labeling these results because the difference between supplemental and the main index is now so narrow.
It gives us one less thing to worry about.