Basic backup services such as Carbonite and MozyHome are geared toward the home user, and they provide a simple, fuss-free experience. Full-featured backup providers, like SOS Online Backup, allow more user control and customization and are typically geared to business users. Most online backup services have client software that allows users to access the service as if it were on a desktop, but the user-friendliness of each interface varies. Typical users don't want to spend a lot of time configuring their backups, and reviewers are quick to point out which interfaces are frustrating or hard to use. Some online backup services offer a certain amount of free storage space or a free trial period, which is a great way to try out their interfaces to make sure you're comfortable with them.
Most services have the same basic features. They allow you to either manually select files to back up or schedule a full backup. The majority do incremental backups, storing changes to a file already backed up on the system within a short time after the change is made (ranging from seconds to hours). Online backup services also typically feature a fully automated backup operation that kicks in when the system detects idle time or low processing activity on your computer, although services with more advanced features let you play around with these settings. Most online backup services also offer file versioning, and you can restore older versions of your files.
File-syncing services are becoming increasingly popular, and these services -- like Dropbox, Google Drive and SugarSync -- offer online backup in addition to file syncing, file sharing and multimedia functionality. They can be a great choice for frequent travelers or those with multiple computers, but they are typically more expensive than basic online backup services, and they don't provide as much storage space.
Most storage services use at least 128-bit SSL encryption to transfer files and another form of encryption to protect data residing on servers. Some services also allow you to choose a private encryption key. This encrypts data on your machine rather than on the company's servers, thus providing a higher level of security during transfers. However, if you lose or forget that encryption key, the backup service can't supply it, and you'll lose access to your stored files.
Here are some other things experts say users should consider when looking for an online backup service: