Unfortunately, Google terms and conditions says, http://www.google.com/intl/en/policies/terms/
"When you upload or otherwise submit content to our Services, you give Google (and those we work with) a worldwide license to use, host, store, reproduce, modify, create derivative works (such as those resulting from translations, adaptations or other changes we make so that your content works better with our Services), communicate, publish, publicly perform, publicly display and distribute such content. The rights you grant in this license are for the limited purpose of operating, promoting, and improving our Services, and to develop new ones. This license continues even if you stop using our Services (for example, for a business listing you have added to Google Maps). "
i.e. if we store data there, we are using their service and we are giving Google "rights of ownership" permanently even after we stop using their service in future. It is definitely not good.
How can anyone give license of their personal stuff to third party?
It will be better if there is a standalone storage service which just stores,backups securely and forgets us when we opt out of their service. As far as I understand, Google drive won't fit in there. Their appetite for our personal information for advertising is not comforting.
If I misunderstood their terms, I am willing to change.