12. A machine-based method for converting data from a first form associated with a data source to a second form for use by a target data system, comprising the steps of: receiving content associated with said data source; obtaining first information from said content; wherein said first information identifies a subject matter context of said content; obtaining second information from said content; wherein said first information identifies a subject matter context of said content obtaining second information from a location, external to said content, using said first information, wherein said obtaining second information comprises accessing conversion rules specific to said subject matter context where said conversion rules are included in a private schema, established based on external knowledge of a subject matter area independent of analysis of a particular data set to be converted, and specific to an entity or group of entities less than the public as a whole, and the private schema establishes a structure for understanding at least a portion of the subject matter area; and converting said content from said first form to said second form using said first information and said second information.
12. A machine-based method for converting data from a first form associated with a data source to a second form for use by a target data system, comprising the steps of: receiving content associated with said data source; obtaining first information from said content; wherein said first information identifies a subject matter context of said content; obtaining second information from said content; wherein said first information identifies a subject matter context of said content obtaining second information from a location, external to said content, using said first information, wherein said obtaining second information comprises accessing conversion rules specific to said subject matter context where said conversion rules are included in a private schema, established based on external knowledge of a subject matter area independent of analysis of a particular data set to be converted, and specific to an entity or group of entities less than the public as a whole, and the private schema establishes a structure for understanding at least a portion of the subject matter area; and converting said content from said first form to said second form using said first information and said second information. 18. A method as set forth in claim 12 , wherein said rules are operative for identifying an impermissible attribute or attribute value based on said subject matter context.