Dave != XML; Dave == RSS
RSS ⊂ XML
There's JSON Schema which is serviceable, but unfortunately lacking a bit in the tooling department: http://json-schema.org/
I don't know if there should be standards for json objects. JSON always reminded me of duck-typed objects whereas XML reminded me of strongly-typed (via the DTD) objects.
But yeah, json is becoming the syndication format.... Are there standards for json objects yet?