Prior art: you come and go

What a surprise! On May 23, the article How did Woo Suk Hwang trick the scientific world about stem cells arose from the Google Dead. You come and go. Or is this the smile on the Cheshire Cat? Forgetting about the "rank" in the search, one will find that the absolute identity of Google search results depends on "when" the search is done. Sometimes the article is there; sometimes it goes away, and sometimes it comes back. It adds a whole new dimension to "the dog ate my homework." And, I can't wait for this issue to be litigated in a patent case. Is it prior art if it was there (and indexed by Google) and then not there? Sort of like "what if" the librarian at the German university threw away the entry of the thesis in the card catalog so no one had a systematic way of finding the thesis.