The problem with most of these cloud initiatives from Microsoft is the missing integration with WinXP.
LiveMesh and Skydrive desktop integrations are fine on Win7, but there are still lots of XP users out there, and most of this stuff does not work on XP.
SkyDrive is a browser-based cloud store, not a desktop application. So you should be able to use it just fine on XP, provided you are running a modern browser.