cloudHQ is a service which synchronizes and replicates data between multiple different cloud services and cloud accounts in real-time.
This is the easiest back-up redundancy I've seen and the third party apps they cover are all the most popular cloud storage services. From the company website for my lawyer peeps:
Is my data secure?
We run latest stable releases of our server operating system and database software. All software we use is continuously monitored for security problems and is regularly updated with the latest security patches.
All the communications between you, cloud services, and our servers are encrypted with SSL.
cloudHQ uses industry standard OAuth password-less authorization protocol when connecting to Google Docs, Box, Basecamp, and Dropbox. This means cloudHQ has no access to your passwords for these services.
We do not not permanently store your files. When cloudHQ access your data via API, it might temporary cache part of the content, but we never stores any of your files permanently on our servers.
Also, to ensure high-level of security, cloudHQ uses Google Federated Login password-less authentication for user authentication. This means that somebody can access your cloudHQ account if and only if that person is logged into your google account.