I just signed up for the Windows Live Folders beta. For now I got 500MB of online storage which I can use to files and share it with who I want.
I hope we will increase the 500MB space very soon, so I can upload my stuff and use it as a secondary backup location. The cool thing about Windows Live Folders is that you can assign either everyone on the Internet or some of your live messenger contacts to be contributor to a folder you created. Or you can only share your stuff with who you want. The upload experience is still basic, no multiple files upload and a limit of 50MB per file. Anyway I am going to start using this.
If you want to use it http:/folders.live.com and be fast because the team will only accept a limited amount of new beta users.
Here are some more screenshots: