While doing research on Java implementations of the XMLStorageSystem API, the backbone of Radio UserLand web hosting, I found something unusual: Full support for the API in a commercial server product.
As shown in the documentation, the OpenLink Virtuoso "universal server" supports the XML Storage System, MetaWeblog, Blogger, and Moveable Type APIs, which enables it to host weblogs created with Radio and other weblogging tools.
This is my first exposure to Virtuoso, but in an article for InfoWorld, Jon Udell makes it sound like Radio's big brother:
At the core, it's a SQL engine that not only supports ODBC but can attach foreign databases through ODBC. Then came the layers: an e-mail server, a news server, an application server, a SOAP stack, Java and .NET bindings, a WebDAV server, and XML storage, indexing, and transformation. The goal was always business process integration, but that was difficult to explain.
Data moves from a SOAP service in Radio UserLand, through an auto-generated WSDL wrapper, into a database stored procedure, which calls out to the Web through a C# extension and stores results in an indexed XML database. Then an XPath-enabled SQL query gathers results, converts them to XML, and virtualizes them as a WebDAV resource, which Excel finally reads and analyzes.
Pricing starts at $5,000 for the server and $600 for the client.