caveman - 3:19 am on Oct 8, 2004 (gmt 0)

>or there have been significant changes to the PR algorithm

So far, that's my vote. Wild guess is that we're seeing the beginnings of their new approach.

Early, wild speculation (sorry):
--age of pages/links playing a more pronounced role now
--sites are being measured to an extent (not just pages)
--backlink PR may be being modified by qualitative factors.

I know, I know, it's out there...