Although I'm not a official "Web Worker" I subscribe to the Web Worker Daily RSS feed. They often have good tips and hints that make online life a little easier. Today they have a post about Online document services such as Google Docs. As cloud computing becomes more and more popular there are more and more services coming online and there are more and more documents being stored in the cloud. I have a Google Docs account and have a few things out there but not much and nothing that I would consider personal or sensitive. I doubt that I ever will put anything of that nature out there. I just don't trust the model.
These things scare me for other reasons also. Lack of control over what happens to them. The fact that they are in the cloud means that there is more opportunity for others to get to them and either steal them or alter them. Not to mention that even though I'm very cautious I'm still human and still make mistakes from time to time. I'd hate to put something sensitive or personal out there and forget to mark it private. Do a Google search (there's another one I use all the time) for public calendar events or docs and see what you find. It will make you shake your head in wonder of what you will find. I guarantee most of those were never meant to be seen by the general public. They are there because of a mistake made by a person.
Anything online has it's inherent security weaknesses. It's still the Internet and no matter how secure you try to make it there are those who will prove you wrong. In my opinion personal, sensitive and business related data does not belong in the cloud.