Tweeting isn't for everyone. I myself haven't completely warmed up to this intertube sensation. It might take a lot longer for Japan at large though, as a recent survey by the iBridge monitor group revealed that just 2.6% of Japanese people ever used Twitter (current and in the past) and only 16% even know what it is. Of those who used the service, more than two-thirds reported having at least four followers.
Given how much Japan uses its cellphones, I'd have thought Twitter to be an immediate hit, since it can direct messages via SMS. Plus, with kanji, one can say a lot more in 140 characters. Then again, Japanese also have an unparalleled level of mobile net access. Do they have a problem with reading all the messages from the bottom up? Perhaps they have something better that they've been using all along?
What do you think it will take for those moon people to get our @Japan messages?