There is interesting analysis/guess on why google behaved differently at this Webmaster Forum thread: Why Google has become its ‘own worst nightmare competitor’. The post, written by Chris_D, explain the it was analogy of technology evolution take of Intel and Google, where:
if you don’t take advantage of the technological advancements you know will happen - your competitors will
Many people noted the changes of searching recently in Google, do they just simply mess up? Or is it some development going on with the competitive pressure?
Reading Summary - Jan 19, 2006
Snakes and Rubies Talk - Jan 08, 2006
Symantec - Dec 28, 2005
Weekend Tech-and-reading activities - Dec 04, 2005