Writing in The Guardian, Cory Doctorow provides a good explanation of why cloud computing might not be so great for individual users. Basically, companies are hoping to use it to wring more money from people, for services that were previously free. As he explains:
[T]he main attraction of the cloud to investors and entrepreneurs is the idea of making money from you, on a recurring, perpetual basis, for something you currently get for a flat rate or for free without having to give up the money or privacy that cloud companies hope to leverage into fortunes.
That’s not to say there aren’t potential advantages. It may well be worth a montly fee for well implemented and highly secure backup, especially for those who aren’t too computer savvy or don’t have access to Apple’s excellent Time Machine product. (Doctorow talks about using Amazon’s S3 service and the Jungle Disk tool.)
Really, backup seems like the cloud computing application with the most value for users, since encrypted backups elsewhere will probably be safe if you are robbed or have your house burn down. Another application with more limited utility might be buying access to huge amounts of computing power, which could be useful for some researchers.
Incidentally, Time Machine isn’t quite good enough for protecting irreplaceable physical data, since your external hard drive could be destroyed in an accident at the same time as your computer, or stolen. While I use Time Machine for daily backups, I also back up critical files (such as my photos) to a hard drive I keep at work and update every few months. A fairly easy way to do this is to keep all your irreplaceable documents in one place – such as username/documents/original/ – and then copying it over to the third drive every few months. rsync is an ideal way to do this, but it isn’t very user friendly.