Google announce the end of the supplemental index

In a curiously timed announcement, just when many people are turning to thoughts of Xmas rather than SEO, Google have said that from now on all search queries will access the full index for relevant results, effectively ending the problem of good quality pages being ignored because they’ve been relegated to the supplemental index.

Supplementals have been a serious problem for the last few years for many sites which have either a deep navigation structure or insufficient inbound links – both situations that result in pages with a low PageRank; which is known to have been a trigger for dropping out of the main index and into the supplemental one. Because Google was only employing the supplemental index when there were insufficient relevant pages in the main index for a query, any pages with rich content but poor PageRank were effectively being excluded from achieving good search results.

Some commentators have suggested that the supplemental index goes hand in hand with PageRank to enable a fast enough response time to queries – Dan Theis has a blog posting on the subject which makes interesting reading and it’s intruiging to wonder what Google have been doing under the hood if his theory was right and how they’ve overcome the performance problems it suggests.

So far I haven’t seen any evidence of change in search results, but that may be because I’ve been used to designing with a view to avoiding the problem. However I’ll be revisiting a number of sites which I know have suffered in the past to see if matters improve for them.

It has to be said that a number of SEO commentators are sceptical about whether there will be any real benefit or if it’s just window-dressing. Andy Beard is one of those who also isn’t seeing any change in the SERPS. However to be fair there may be a delay in getting any changes rolled out through the vast number of data centres that Google uses. One thing I’ll be watching closely is the listing of internal links in Webmaster Tools, because I’ve long suspected that this only lists pages that come from the main index. If that is true then we should see all the pages in a site appearing in that listing. I’ll keep watching this and return to it in a few weeks time.