I was also under the impression that Dropbox uses S3, but then I read this article in Wired: http://www.wired.com/wiredenterprise/2012/06/flash-data-centers/ ht

I was also under the impression that Dropbox uses S3, but then I read this article in Wired: http://www.wired.com/wiredenterprise/2012/06/flash-data-centers/ http://www.wired.com/wiredenterprise/2012/06/flash-data-cent... "But if you walk into the right building and down the right aisle, you’ll run into a giant Dropbox logo. Clearly, the file-sharing upstart is proud of its data center gear. [...] Inside its cage, Dropbox is running servers equipped with solid-state drives, also known as SSDs — super-fast storage devices that could one day replace traditional hard drives. The company doesn’t use SSDs in all its servers, but it’s moving in that direction."