chiyo - 1:08 pm on Oct 3, 2002 (gmt 0)
This is not something recent. For several months, Google will add new pages if they find them linked from pages they "fresh crawl" from. They will appear for around 3 days and then disappear to reappear again permanantly after the next monthly update. If it keeps on finding reocurrences of the new page from "fresh crawls" they may reappear again for 3 day periods before the next update, from all apperances here.