There was an announcement this week from the SDS development team in Microsoft that there will be a change in direction for SDS. Instead of the schema-less database I have been talking about over last few weeks it will be moving towards full blown SQL Server hosted in the cloud. The big advantage is that it will make it much easier to migrate existing database apps to the Azure platform.
This decision also makes sense when you consider that a lot of the features of the existing SDS are already available as part of other Microsoft data access technologies. For example Azure already has a schema less database technology in the form of Azure Table Storage. You can also get the REST based database interface by using ADO.NET Data Services.
If you are getting confused by all the different data access technologies Microsoft is providing, you are not alone. I really should do a post that describes the different technologies that are out there.