There is no need for Apple to "kill" Microsoft. Ballmer himself seems to be doing a good job for the last 10 years since Gates left. And with the recent over-priced acquisition of Skype, seems well on the way to killing his own company.
iCloud is a defensive play. It's to prevent Facebook and Google from getting at Apple users' data. At the same time it's boosting Twitter's star. Apple's MO is to be in control of its own destiny, so I wouldn't be surprised if Dave Winer was right and Apple already has some investment in Twitter, considering how tightly integrated it is with iOS 5.
iCloud is a defensive play. It's to prevent Facebook and Google from getting at Apple users' data. At the same time it's boosting Twitter's star. Apple's MO is to be in control of its own destiny, so I wouldn't be surprised if Dave Winer was right and Apple already has some investment in Twitter, considering how tightly integrated it is with iOS 5.