Which desktop and mobile operating systems do you use? Most cloud storage services come with an application (called a client) that manages backups and file transfers, but not all clients are compatible with non-Windows operating systems. In addition, if you want to use the backup service from your tablet or mobile device, you'll need to choose a service that provides specific apps for these.
How much data do you want to store online? If you just want to store a few files, then consider one of the free cloud storage services; if you plan on backing up your entire computer's contents, then consider a paid subscription to one of the services, as you can usually choose from several storage amounts. For those who work from their computers, tablets and phones, a service should offer file synchronization across these platforms.
How sensitive are your data? Many reviewers note that data kept on a remote server, as is the case with a cloud storage service, are more vulnerable to unauthorized access than data that's on your own computer. All cloud storage providers use some sort of encryption (and sometimes multiple encryptions), but you might not want to take a chance with your most valuable data.
How fast is your Internet connection? Initial backups of large files can take hours or days, even on a broadband connection, and it's best to perform large file backups at night or anytime you won't be using your computer for anything else. Keep in mind that subsequent backups are done incrementally, and go much faster.
Are you comfortable backing up online? Online data storage saves time and space, but experts say you should never put all your digital eggs in one basket. Most services do not promise that they can restore your data should a hardware, software or business problem occur. Consider alternatives such as CDs, DVDs, flash drives or external hard drives.