Skydrive's genesis was Foldershare (I think it was Foldershare --> Windows Live Folders --> Windows Live Mesh --> Skydrive), which launched in 2002.

Really? Intriguing! I'm used to MS jumping onto bandwagons late ("Oh, so Netscape is doing well? Maybe this 'inter-net' thingy isn't just a fad. Get Spyglass on the phone.") but maybe this time they had the product ready to go. Certainly they didn't push it as hard as Dropbox did; I didn't notice it existed until I started seeing it activated by default in Win8.