The US DS penetration wouldn't quite be like the one in Japan, aside from the fact that Japanese are much more gadget mad. Japanese spend so much time on the subway! That's time to kill, what's more perfect than a DS. Here in the US... other than NYC, Boston, plus a few other cities, most people drive.
That being said, you can say that the DS has come of age in the US when you regularly see people playing the NY Times Crosswords on the DS in a NY subway instead of doing a paper and pencil one. (the NY Times Crosswords for the DS apparently is coming out soon)
Actually, have people start seeing adults play the DS on NY subway? I don't live in NY, but somehow if somebody's doing that late at night the chances of his DS getting robbed seem pretty high.
the Wii is an epidemic.
