James Clark has a great post on XML and JSON.But I have one point to pick at.
"JSON's primitive datatype support is weak."
Next, "the set of primitive datatypes is not extensible". But this istrue for XML itself. Until you mix in XML schema. It's schema thatallows you to interpret a string in XML as some sort of other data type. JSON has no standard schema. Yet. It's easy to imagine though. Defined in JSON, of course.