Today, there are many services that let you store your files "in the cloud," and access them from anywhere. For example, Dropbox, Box.net, GoogleDocs, GoogleDrive, MobileMe and iCloud are popular and inexpensive cloud services used everywhere. Even Gmail is considered a cloud storage method. These services are very useful, but sometimes they can be about as secure as... storing something inside an actual cloud (not very secure). Cloud computing services have opened unlimited opportunities to users while creating unlimited risks to those users' data.
Before cloud storage existed, in order to provide storage to users an organization would need to: purchase the storage; create a data center where the storage would reside; run servers that would utilize the storage; and employ server administrators, storage experts and data center operators. Today, an organization or even an individual can have the equivalent of a data center's infrastructure, just by using a cloud-based service. It can potentially save thousands of dollars and man-hours, and might even be completely free while being available 24/7. But there are security issues that must be addressed before these services can be verified as truly secure, including data ownership, data separation, data protection, and backup.