From the new Danketsu song
Mami:
"Lately everyone's talking about Futami Mami!
The crazily popular middle-schooler!
I guess I'd like a boyfriend and to be famous, but...
As long as I have my nii-chan, I guess I don't need them!
Mmhmmhmm~
If you want a leader, then just leave it to Mami!
I'll get you all to Brazil, I swear!" (I don't get it. I really don't get it, but that's seriously what it says. Luckily, it gets worse...)
Ami:
"I'm Futami Ami, her sister! Hey!
Could this mean... could it mean...?!
I'm a little sister character!
So my popularity with _________ is guaranteed! (The amount of spaces in the Japanese is exactly the right number of characters for 'lolicons'. Just sayin'.)
You're making Ami the leader, huh?
Looks like you know what you're doing!
Ami'll get you all to Brazil, I swear!" (The exact same line as Mami's! Yay... Brazil?)
This made me think of 'The world is all one', perhaps 'the world' implies the idols are now going worldwide? and Brazil could have the final/an important contest.
furthermore if you look at PV 1
http://www.youtube.com/watch?v=kU2_30vbKpsyou can see that Japan is broken up into sections, and then even further on a grid.
Then it might just be me but behind Yukiho, Hibiki and Mami is that China?
and behind Makoto, Takane and Miki, is that America?
and behind Chihaya, Yayoi and Haruka is that Australia?
PV 2 we can see pretty much the same thing
http://www.youtube.com/watch?v=zhQmOwin_Ag&feature=fvstNow it might just be me, but perhaps you fight with the rivals over territories or something? Where your influence is spread?
And the twins mention of Brazil could be a reference to an important/the final event.