New iPhone, what to do?

Apple iPhone - New
When you get a new iPhone4, do you have to always
1. Put in a SIM, even if you want to use only Wi-fi
2. Register in itunes even if you do not intend using Appstore.

If yes then why?

New iPhone
If you buy from a carrier the answer is yes to both.

But not if you buy without contract.

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You still have to use iTunes to activate it even if it is carrier unlocked or bought from Apple or via web site - every apple product does, even the WiFi iPad has to be activated in iTunes just the way Apple requires registration of the devices...