Visit https://www.box.com/personal/ for more information, to sign up, or to watch a demo video.
From the Box website:
“Box lets you store all of your content online, so you can access, manage and share it from anywhere. Box is a simple, scalable and affordable solution to manage documents, media and all your content online. Share files as a link. Sync files on the desktop. It’s file sharing, reinvented.”