A couple of days ago I got home from Japan. From a mobile perspective, Japan is very interesting. It's about as different from the rest of the world as USA. They just do everything their own way. I'm not going to try to analyze that stuff, though, as I believe that there are others who can do that much better than me. I didn't exactly spend much time studying mobile phone usage when I was there, instead I concentrated on sightseeing and drinking beer, so I'll just report on some observations I made:
One thing that I've talked about before is how colourful and beautiful the phones are. The Japanese also seem to use them a lot. And it's not like they mainly use them for placing calls. I'm not exactly sure what they use them for, but my brother's wife told me that they don't use SMS much in Japan. Instead they use email, but not with their regular email account, but with another address that's specific to the phone. So it's the same as SMS, except that there's no arbitrary limit on the length of messages. I guess the disadvantage is that you actually have to know someone's email address to be able to send an email, while with SMS you just need to know the phone number.
Then there's all the whimsical stuff about the straps, emoticons etc., but I'm not going to go into that, but it fits in well with Japanes pop culture, I guess.