When living in one country (US) and wanting to create a site for another country (UK example) would it be best to use that country's domain (co.uk?) or stick to regular domains (.com, .net, .info, etc?)
is not a rule i think , the language used is a rule if we don't talk about UK, Australia, Canada and other english speaking countries
It's not so much of "do I have to?" and more of a "If I want more targeted traffic from that country?" type of thing...