A WebmasterWorld thread has a nice amount of Webmasters noticing an increase in the number of supplemental pages being returned by Google. How does one measure the number of supplemental pages in the Google index for their site when Google hid that information from us?
site:www.domain.com gives 711 pages
site:www.domain.com/* gives 104 pages
as I know the 104 are indexed and the rest up to 711 are in supplemental index
There has always been terrible confusion over the supplemental index and Google is partially to blame for that confusion. Is this something? Are you seeing the same thing? Is it impossible to measure supplemental results?
Forum discussion at WebmasterWorld.
Update: Google made a major announcement about the supplemental index just an hour ago at the Google Webmaster Central blog that is probably related to these findings.