Microsoft does RDF

Microsoft Connected Services Framework "The Profile Manager component provides profile management services. Connected Services Framework uses Profile Manager to store custom information about users and their preferences. Profile information is held in a Resource Description Framework (RDF) store, which is implemented by a Microsoft SQL Server database. Profile Manager provides facilities for creating and managing user profile information and for propagating profile information to Web services that cooperate in a service-oriented application."

Behold MS SPARQL: "

string sparqlQuery =
    @"PREFIX ex: 
    CONSTRUCT {
     ex:fullName ?Name
    }
    WHERE {
     ex:fullName ?Name
    }
  ";

"

Via, links for 2006-12-07. Microsoft using RDF and SPARQL, "...according to timbl Vista will be using XMP (RDF inside) to store metadata about photos etc."

Also, I recently noticed their implementation of EXCEPT (SQL's set difference) EXCEPT and INTERSECT (Transact-SQL).