The 2012-02-12 version of the Azure storage services includes these changes:
Copy Blob now works asynchronously, and can copy from any Azure storage account.
Containers can be leased, and all leases support shorter or infinite durations. You must now provide a lease duration.
A released lease cannot be broken or renewed. Previously these operations were allowed.
If you break a lease that is breaking or already broken, no error will occur.
The lease ID of an active lease can be changed.
A lease ID can be included on an operation to acquire a lease.
When breaking a lease, you can specify a period during which the lease should remain active.
Table and Queue services now support shared access signatures.
A shared access signature can live longer than an hour, even with no stored access policy.
The Blob service now provides MD5 hashes for the Put Blob operation.