.ar is Argentina, if I'm not mistaken. If I'm correct on that assumption, it may be fair to assume that Spanish is the common language of Argentina. So, if A and B are true, it may be logical to assume an Argentinian would write a webpage in her native tongue, being more familiar in the vernacular of that area.
Sorry, I was just helping someone prepare legal proofs in preparation of his LSAT, so I'm in lawyer dick mode.