Yes, we have covered this topic in the past, but it is an important subject as more and more users are using Cloud services. Users should be informed of some helpful tips to keeping data secure (backups & data transfers), keeping sensitive data as private as possible, and have data available if your service(s) are not readily available. One of our highly recommendations is to always keep a local backup of your data in case your service was temporary unavailable, and this also allows you to have more control of the data in the case of sensitive information.
Some basic advice offered in a recent article by Network World website includes: avoid keeping too much sensitive data in the cloud, using basic password security rules (make passwords complex, using different passwords for different accounts, etc.), and using data encryption techniques, whether it be a software solution or using a cloud service that encrypts your data.