Just this day, a Windows update for IE7 came in and Windows was asking me to install it. After that, my Adsense ads no longer display on my site! (by the way, Google reapproved my account)
It is possible that this is just a bug, a security setting, I dont know. But if Internet Explorer blocks Adsense on purpose, Google would not be happy cause they'd lose the $2 billion Adsense brings each year. Google would be ready for the war.
And why would they declare war? It's would because of the Microsoft-Yahoo merge(see my previous post, "Microsoft and Yahoo [may] beat Google"), which main purpose was to beat Google.