Microsoft has attempted to make a successful cloud platform - their commercials all proclaim, "To the Cloud!" - and yet, they fail, while someone else takes their technology and (potentially) succeeds.
I don't really think that MS has targeted Windows Azure towards the general consumer market, though. It's basically the same as Amazon Web Services. Apple using that tech gives them an incredibly strong marketing tool, especially for companies that are trying to decide between using Amazon or something else for cloud-based services.
http://explore.live.com/windows-live-mesh?os=other
Am not sure how much traction it finally got
If Apple succeeds with iCloud, and that's a big if given their own track record in the internet space, it'd ought to be pretty awkward for Microsoft.
From a strictly logical sense, it's meaningless. But symbolically, it says a lot. The fact that Microsoft failed at something and then got bested by someone using their technology is symbolic of how far Microsoft has fallen.
Services like Azure are what Microsoft should be about.