I have always had the feeling that becoming an Amazon customer is a bit like joining the Borg: resistance is futile. But Amazon really does believe in customer service, and is particularly good at identifying trends and then developing services to meet the new market demand. Amazon is beginning a big push for their Cloud Drive service, which lets you upload files to an Amazon server and then access them from anywhere. In concept, it is no different that the file storage Apple has offered first via dotMac and now via MobileMe. But Apple has never paid much attention to MobileMe, and my own experience with MobileMe has been decidely mixed. MobileMe and Cloud Drive are both essentially virtual hard drives, and they differ from the backup services like Carbonite because backup services are not designed to provide routine access to your files. On the other hand, the backup services provide more tools to make sure everything gets backup regularly. Some people are going to use both, and some might settle for the virtual hard drive approach to save money.
As I've been writing recently, cloud services are only as good as your broadband connection. The interesting thing about cloud-based virtual hard drives is that the big companies have no real advantage over a small firm with servers closer to customers. If I was starting a business, I'd be looking at something very different from the massive data centers Apple, Amazon, and Microsoft are building. I'd be looking at putting servers and services on community broadband networks and getting my cloud services as close as possible to my customers. Why? By doing so, I can provide better services at lower cost than the big guys.