For years, I've had email stored on servers out there in this somewhat nebulous internet cloud, and can't really see a way to have email otherwise. A few years back, I increased the amount of "cloud" presence my emails have by switching from POP (so that my emails were stored on a server somewhere only until I came to pick them up) to IMAP (so that they are stored there until I move them out of my inbox into a local mailbox).
More recently, I have started to store my calendars, to-do lists, and contacts on various "cloud" servers. I even have file sharing, via DropBox these days.
Should one be concerned about the privacy implications of all this? If so, what can one do about it?