Can't beat a quote like this from the creator: "We are planning to stay alive for 100 years this is a very long term play. We are planning to kill the OS by letting users execute any file type in the cloud"
Microsoft have released some great products in the last few years; Xbox and Windows Phone are a couple. Xbox has obviously done extremely well and WP is only going to grow with their partnership with Nokia. Correct me if I'm wrong, but these were both the result of starting from scratch with a smaller, more agile team who have permission to do something different and new. This works; even for Microsoft.
I also feel that maybe similar to Marco Arment's comments on the benefits of the new features in iOS on Instapaper, this may be the case for MSFT. If Apple can pave the way to making consumers' understand or at least appreciate what the cloud can do for them, then Microsoft and Google and others will have an easier time talking about their products. Before the iPhone came out, people couldn't see why and didn't want a "smartphone". Now everyone wants one, whether it's an iPhone or Android (and in the next few years Microsoft).
Microsoft does have some great products in this sphere I believe, Mesh and Skydrive being two. I haven't used either, but from what I've heard they do have some great potential. If off the back of Apple's announcement they can make them look good and continue developing on them, they will be able to sell it, even if its just by saying its the same as iCloud, but made by us. Apple does have a reputation of creating beautiful, easy to use products, but they are also seen as expensive and sometimes unneccessary. Android has taken off by being an alternative - Microsoft have the potential to be that alternative to iCloud. They have the pieces and experience shows MSFT does much better when they are the underdogs (Xbox and WP).