Afaik, it's up to the country to determine the rules for the tld. Some require strict rules (eg, .us requires making public a current mailing address, something making me consider getting rid of mine as I don't want that so public), and others (eg, .io and .fm) simply use it as a way to make some money.
To be accurate it is not that you have to have content in Catalan (although that seems to be the _main_ purpose of the sponsored TLD) but you have to "be a part of the Catalan
Linguistic and Cultural Community" as set forth in the registry agreement between ICANN and domini.cat [0]
