I agree Enrico...I just feel it irresponsible to use this "world phone" terminology on Apple's part...
GSM phones have been called world-phones since the 1990s.
A world phone is phone that can be used in many different countries. Whether unlocked or not, the phone will still work. That's all it means.
I really think the US needs a law change forcing unlocking of phones to prevent this carrier BS
Why? Cell phones, including the iPhone, are offered factory unlocked in the United States. If you don't want a carrier lock, then don't accept the subsidy the cell phone company rewarded you with and pay full price.