Something we’ve come across recently is a search query to check for URL’s which are listed in Google’s main index. This appears to remove any webpage’s which may be listed in Google’s supplemental/secondary index.
The query to find this is: site:domain.com/*
At the moment I’m unsure how accurate this is, the only reference I can find is a comment from Halfdeck on Jim Boykin’s How to Find if a Page is in Google’s Secret Supplemental Results from two and a half years ago. And since then, despite pleas to bring it back – Google have removed the queries which have helped us to find supplemental pages.
But looking at the results, I think there is some truth to the results – even if these are not entirely accurate.
Example supplemental query – BBC.co.uk
For example, BBC.co.uk has 47.9 million indexed pages – but the supplemental query lists only 1.43 million results:
