It's like dropbox...but you get
25GB 7GB free.
Although, you have a couple gotchas
First there isn't an app like with Dropbox...there is a webui and you can also Map a network drive and make it act like the dropbox app.
It's hosted by Microsoft...IDK if everyone will agree this is a serious catch...at least in my eyes it is.
https://skydrive.live.com/