The Windows Azure Blob Service supports a simple two-level hierarchy for blobs. There is a single level of containers, each of which may contain zero or more blobs. Containers may not contain other containers.
In the Blob service, a blob resource is addressed as follows:
http://{account}.blob.core.windows.net/{container}/{blob}
{account}, {container}, and {blob} represent the name of the storage account, container, and blob.
This addressing convention works for most uses of blobs. However, when using Silverlight the runtime requires that a cross-domain policy file reside at the root of the domain and not beneath a container, as would be the case with the standard addressing for blobs. The cross-domain policy file allows a web client to access data from more than one domain at a time. (http://msdn.microsoft.com/en-us/library/cc197955(VS.95).aspx) Microsoft added support for a root container, named $root, to the Blob service, so that it could...