If you have even a passing interest in your online privacy (or, more importantly, lack of it), do yourself a favour and go listen to the latest Security Now podcast (episode 414 is the one I'm referring to, which doesn't seem to be shown there yet, but no doubt will be soon).
In fact, load up the last half dozen or so episodes on your favourite podcast listening device.
There is much food for thought contained within. I think it's probably safest to now assume that anything, and I mean anything, you do online is probably getting stored and possibly seen by people other than those you intended it for.
What this means for the future of "cloud storage" is unclear. Encryption before storage seems about the best option for now. Steve, in the above mentioned podcast, mentions that Google are looking at encrypting Drive stored documents, which is a good move.
I'm a heavy user of such services and I store a lot of important documents in the cloud. If I have to encrypt everything before I send it, that reduces the usefulness of having it there dramatically, as most mobile methods of retrieving such data don't allow me to decrypt the content and one of the reasons I'm so heavily invested in cloud storage is so I can access everything I need to when on the move.
Any suggestions on the best way forward?