Webmasters can stop fretting about Google’s supplemental results – they’re not really there anymore. Google has lifted the veil between indices.

Google introduced its supplemental results in 2003, much to the chagrin of webmasters actively looking to have more of their content indexed for search. In what the company then called "a new Google experiment," a pair of indexes were created, one for the search engine’s main results, and a second for more obscure queries.

And then four years of confusion ensued – at least for webmasters. The new index appeared to be "where Google puts the trash."

Though Google repeatedly said that webpages placed in the supplemental index were not placed there because of some kind of penalty, webmasters quickly realized how badly their search traffic suffered.

Though not an outright penalty, voices from inside Google suggested that pages in the supplemental index often had certain things in common: few or no quality backlinks, orphaned pages, URLs with too many parameters, low PageRank, duplicate content, et cetera.

Pages in the supplemental index were not crawled as often, and not returned in the main results unless not enough results were found for a query. Thus, a new SEO focus was on how to get one’s pages out of "Google Hell" and into the main search results.

Back in July of this year, Google stopped labeling them as "supplemental results" as such a label implied that the results were inferior. The crew was in the process of overhauling the system to provide deeper and more continuous indexing with fewer restrictions and a greater ability to handle URLs with more parameters.

This was the first real signal that the supplemental index was on its last legs, as engineers noted that "the distinction between the main and the supplemental index is therefore continuing to narrow."

Yesterday, even as forums around the net were upset by an apparent increase in the number of pages relegated to the supplemental index, Google’s Yonatan Zunger announced that "the elimination of the artificial difference between indices" was complete.

Zunger writes, "rather than searching some part of our index in more depth for obscure queries, we’re now searching the whole index for every query.

"From a user perspective, this means that you’ll be seeing more relevant documents and a much deeper slice of the web, especially for non-English queries. For webmasters, this means that good-quality pages that were less visible in our index are more likely to come up for queries."

So that’s good news. Google will search both indexes for all queries rather than only bringing up supplemental results for difficult queries. Zunger said it took "some truly amazing technical feats," but webmasters no doubt will feel it’s four years overdue.