konrad - 5:01 pm on May 7, 2006 (gmt 0)

To be more precise most of those indexed pages are duplicated anyway, because I don't use "non www"->"www" redirections, so G sees every page twice (e.g. "www.mypage.com" and "page.com"). So maybe this drop in indexed pages is because G noticed it, and now removes duplicates. But it doesn't justify drops in SERPS, at least I've never heard that "www"/"non www" causes such serious problems.