JSON has proven to be a highly useful object serialization and messaging format. JSON-LD is a JSON-based format that can be used to serialize Linked Data. The syntax is designed to not disturb already deployed systems running on JSON, but provide a smooth upgrade path from JSON to JSON-LD. It is primarily intended to be a way to use Linked Data in Web-based programming environments, to build interoperable Web services, and to store Linked Data in JSON-based storage engines. JSON-LD is capable of serializing any RDF graph or dataset and most, but not all, JSON-LD documents can be directly transformed to RDF.
This is a Last Call publication for both specifications. All substantive technical work on each specification is complete. Feedback on both specifications is encouraged and should be sent to firstname.lastname@example.org. The Last Call period will end in 4 weeks, on May 10th 2013.
You can learn more about JSON-LD in the video introduction to JSON-LD.