Google Problems with site: Field Search

A (very) long discussion thread at WebMasterWorld, Pages Dropping Out of Big Daddy Index, explains an inconsistency with how the site: search at Google works at the moment. For some background, Google has a large database of “supplemental results” which typically only show up in search results when the total number of results is less than some Google-only-knows number. These supplemental results (tagged as such after the file size) are updated much less frequently and are often duplicates or dead links. However, sites with large numbers of pages find that some of those pages end up in Google’s supplemental database. This discussion thread shows discusses how the site: search is failing to bring up some results from the supplemental index even though the pages might be found by a keyword search.