This allows your Windows Azure compute applications running in our cloud to use the existing NTFS APIs to store their data in a durable drive. The drive is backed by a Windows Azure Page Blob formatted as a single NTFS volume VHD.   The Page Blob can be mounted as a drive within the Windows Azure cloud, where all non-buffered/flushed NTFS writes are made durable to the drive (Page Blob).   If the application using the drive crashes, the data is kept persistent via the Page Blob, and can be remounted when the application instance is restarted or remounted elsewhere for a different application instance to use.   Since the drive is an NTFS formatted Page Blob, you can also use the standard blob interfaces to uploaded and download your NTFS VHDs to the cloud.

More details can be found at: http://microsoftpdc.com/Sessions/SVC14

Anish, S