These sample applications are not anything you haven't seen before. The cool thing is that these were built in only a few minutes each, and can be customized as easily.
Simple CRUD applications:
More advanced example querying SQL Server dictionary to document the database structure:
DB Design Documents
Applications metadata in XML:
Localised address book:
Because these applications are built on top of a standard and robust technologie stack (Microsoft .NET Framework and SQL Server), they can be hosted anywhere and scale to thousands of records and hundreds of users.