2. Simply a way of stating that Japan(Nippon) rules.
3. Sometimes used as a random ass interjection in the middle of someone else's sentence, or when ever the user damn well preases.
4. can also be used to refer to the never ending stream of "ror's omfb's rofr's and 'pwn pwn pwn's'" that an asian might unleash when they feel the need to spam, thus it is called 'nippon pwn pwn'
history: created when someone started shouting "Nippon banzai!" and another shouted "PWN PWN PWN!"
Eric:Nippon pwn pwn!
MIkey:Nippon pwn pwn!