Meta-Meta-Meta....

At what level do we put a peiod on the level of abstractions we have on 
information ? We have Metadata, metada-metadata........
Especially, in the XML World, there is an XML that represents 
Information, XSD that is the metadata fo the information,
Ontologies that are the metadata for the semantics of the information, 
and so on..... Where is the Sky ?
Maybe there is a metadata for the kind of relationships that are 
possible within an Ontology .... and so on......

-Menon