As the introductory video suggests, you can use Dropbox as a backup service. Online backup services are common these days - if Dropbox didn't offer file syncing it would be in direct competition with companies like iDrive and Carbonite.

Using Dropbox for the task of backing up data has both pros and cons. The main advantage of online backup is the fact that your files are hosted at a remote location that is entirely separate from your physical location. Most people who back up data transfer it to an external hard drive. That's fine, but what if your house burns down or there is a flood? Your equipment would be ruined and your data would go with it.

You can also use Dropbox to backup information that is located on multiple computers with a single service. This is much more convenient than plugging an external hard drive into your desktop, transferring, unplugging it, plugging it into your laptop, transferring, and - I think you get the picture.

Of course, there are some disadvantages as well. Backing up large amounts of data is difficult because of the storage limitations on a Dropbox account. Even the $19.99 monthly plan only offers 100 gigabytes of storage, which is nothing if you want to backup music and movies. Another problem: your backup is tied to an account that could theoretically be hi-jacked.