The funny thing is that upon registration of a .cat domain you are required to acknowledge that your website is not related to cats at all. So those domains are, in theory, not in compliance.
One could say by having the websites become popular and viral, and offering versions of the their websites in Catalan, they are spreading Catalan culture to more parts of the internet. We're having a discussiong about it right now, others are reading, pretty big impact from just the TLD choice :)