Since you're probably going to be paying for a backup service for years, cost is an important factor to consider. All the services rounded up here are subscription-based, but they partition their features and fees differently, so it's worth comparing plans closely before committing to one. Most construct pricing tiers based on the amount of cloud storage included, however, or by the number of devices you can use with an account. A few services offer permanent free accounts, but those plans impose paltry storage limits or restrict key features to the paid versions. Watch out for file-size upload limits as well.
Carbonite's lowest tier plan, Safe Basic, runs $6.00 /month ($71.99 /year). There are two higher tiers available as well, called Safe Plus and Safe Prime, and run $9.34 /month ($111.99 /year) and $12.50 /month ($149.99 /year), respectively. Each tier is a bit cheaper if two or three years is paid upfront. Plus, they each have a few extras over the base service like external hard drive and mirror image support.
Bitcasa Infinite Drive is relatively new, but it's one of your favorite cloud storage providers in general, mostly because they offer virtually unlimited stroage for syncing and backups. When we say unlimited, we mean it—some of you are using terabytes of storage with Bitcasa. It's not primarily a backup service though, and while it was built for file syncing and storage, the Bitcasa desktop client does support regular file backups. Bitcasa supports Windows and OS X, and encrypts all of your files before uploading so they stay safe from prying eyes. Bitcasa even keeps revision history, so if you've backed up a file multiple times and need an older version, you can pick it out and restore it. Plus, you can use the Bitcasa mobile apps for iOS, Android, and Windows Phone to access your data on the go.
SpiderOak's beauty is that it's a combination cloud syncing and storage service as well as a backup client all in one. Unlike some of the other services though, you'll have to pay for the storage you use. You get 2GB for free just for signing up, and you can get up to 10GB by referring friends. SpiderOak Plus nets you 100GB for $10/mo to use for syncing and backups, and every 100GB after that is another $10/mo. Plus, you can connect as many computers to any SpiderOak account as you want, so you're not paying by the system. You can read more about SpiderOak's plans here.
Backup software: We run each program through the various types of backups it’s capable of. This is largely to test reliability and hardware compatibility, but we time two: an approximately 115GB system image (two partitions), and a roughly 50GB image created from a set of smaller files and folders. We then mount the images and test their integrity via the program’s restore functions. We also test the USB boot drives created by the programs.
YouTube’s mobile app provides controls allowing you to mark a video or playlist for offline playback. With this feature, you can enjoy your favorite clips, music videos and other YouTube content even when your device is without an Internet connection. In this step-by-step tutorial, we’ll explain how to save videos offline, manage your offline and storage settings, access your downloaded videos and more.

SpiderOak is well known as one of the most privacy-centric cloud storage services, but it's also a great backup service. The same power and features that you get for file syncing and access extend to its backup client, and SpiderOak's "Zero Knowledge" policy extends to your backups as well. Even they don't know what you're storing on their servers, and all of your data is encrypted on their servers and before it leaves your computer. The SpiderOak desktop client has a fully-featured backup tool in it that lets you back up your entire desktop, documents, email, music, or movies right to the cloud, or you can hit the "Advanced" tab and pick the files and folders you want to save, including external drives, network drives, or anything else on your computer. As you add files to your backup job, you'll get a live preview of how much space you'll use with what kinds of files, and whether you have space for it. SpiderOak supports Windows, OS X, and Linux, has mobile apps for iOS and Android, can do incrementals, and if you uncheck a file to stop backing it up, the files will still live in your SpiderOak account, just as an archive. Your backups happen in the background, or when you schedule them.
The iDrive service comes with backup clients for nearly every PC and device, including Windows Phone—a rarity these days. The company provides additional storage for syncing all your devices and PCs, allows sharing of files with anyone, and has the ability to back up to a local drive. The company also has several affordable pay plans. For all the details, read our full review of iDrive. 
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