JSON is a string representation of an object. It is an interoperable serialization format. It is not tied only to javascript. For example there are JSON serializers for .NET allowing you to serialize/deserialize .NET objects.
So it's just a format allowing you to convert from objects to string and back which is convenient if you want to transfer them over the wire.
It is very close to javascript object representation and if you simply eval() a JSON string you will get the corresponding object.
