I tried the MS Skydrive, and the free cloud space I get w/Comcast. Actually I guess I do use it for my Kindle Fire, but only for a few non-personal things like a book or two and one or two games. The other two are painstakingly slow to upload to, and Skydrive is much more awkward to use than it should be. I have a very fast download speed, but uploads are simply too slow. Then there are security and reliability considerations. When I can buy a 2 TB hard drive for just over $100, it's not at all obvious why anyone would want to use this abomination. As for backup, I can do that to an external hard drive, and put a copy on a flash drive locked up in my car (which has a security system). I have on occasion put some data in my safe deposit box, but that's really overkill for me.
Having Wi-Fi troubles?
From the garage to the basement, we blanketed every square inch of the CNET Smart Home with fast, reliable Wi-Fi.