Many services also offer a feature called versioning. This saves incremental changes you make to files as recoverable snapshots of the file. It's useful in case you need to get back information from an earlier version or if your latest file save becomes corrupted. Services vary widely in how many versions they keep and how long they're saved. Best-in-class services, such as SOS Online Backup and SpiderOak ONE keep an unlimited number of file versions forever.
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.
The last thing that I'll add is that the build quality of the software is excellent... any if you that have purchased Abbas' products in the past then you know that the quality of his software, and his customer support, are exceptional. I can’t imagine uploading all my videos all over again since I have over 500 videos in one of my accounts. I really needed this software!!
Backblaze earned praise from many of you for being easy to set up, even for non-technical people. It's built for people who want to get their data backed up, without being forced to search for error codes and cryptic status messages whenever something goes wrong. To that point, Backblaze backs up just about everything on your system. You get some control over what's backed up and what isn't, but the point is to be fast, easy, and hands-off, so everything on your system—documents, music, video, external drives you have plugged in, just about anything. Instead of telling what they do back up, Backblaze actually has a special page dedicated to what they don't back up instead. Backblaze offers unlimited storage for your backed up data, and while by default it only backs up files smaller than 4GB, you can bump that up if you need to. Like other online backup services, it runs in the background, backing up your data all the time (or when you schedule it to, if you prefer), and your data is encrypted so only you have access to it. It supports Windows and OS X, and is smart enough to de-dupe data, do incremental backups, and keep backup processes low on system resources. You can read more about Backblaze's features here.