Let me add (to Alrik) for Europe, that, as often in Europe, all countries have age level ratings, but they are neither uniform all over Europe, nor are the applicable standards as to which should fall under which category uniform.
Because European wide Publishers have to comply to local laws, and make multi-language versions, this leads to the confusion for the clients, that a game shows two (or more) ratings from different institutions and at differing levels on the same packaging.
The laws requiring rating are not as old either - until a year or so ago, a Publisher (at least in most European countries) could have his game rated, but didn't have to. (Except for "mature", I think, but there are those who are of the opinion that, if you want to play a game rightfully classified mature, it is proof of your lack of same <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />)
