Carbonite is one of the web's most popular online backup services, and for good reason. The Carbonite client runs quietly in the background uploading your data to Carbonite's servers to make sure it's safe in case something happens to your computer. Carbonite can automatically back up documents, music, email, and other files (although it manually backs up video), and grants you access to those files and your archives on your smartphone. Carbonite supports Windows and OS X (although its Home Plus and Home Premier plans only support Windows), and make restoring your files as easy as backing them up. Your offsite files are encrypted to keep them safe from prying eyes, and all of their plans include unlimited storage for your backed up files. Carbonite's Home Plus plan extends its features and allows you to back up external hard drives and not just files on your computer, and allows you to back up full system images. The Home Premier plan includes both of those features and adds automatic backup of your video files, and a courier recovery service that delivers you backups on a hard drive to you ASAP if something terrible happens.
Backup services vary widely in how they set up and perform backups. For example, the totally hands-free Backblaze automatically encrypts and uploads all your important files without any input. On the other hand, services such as IDrive and Acronis True Image let you choose specific files you want from a file tree. Note that some services restrict you from backing up specific file types or using particular sources, such as from an external or network drive. Make sure the service you choose supports all your needs.