A post at Stuntdubl entitled "Why Does Google Lie to SEO’s?" really is quite an interesting read. It discusses whether Google are doing the right thing in being so private with regards to information and algorithm updates and generally sharing information between SEO's - whereas Yahoo and MSN are quite open in comparison.

Of course the article does go on to say about the recent activity with GooglyGuy and WebMaster World with discussing the Bourbon update - so perhaps things are changing?