I had a chance to go back to Japan for about a week, and I've attended a couple of tech meetups in Tokyo. What I saw in Japan (I mean Tokyo) was growing awareness, almost overwhelmingly, of "social" and social games. It is known that Japan has one of the biggest twitter users. It appeared to me that there was some sort of social booming happening in Japan. "MOVAGE" via DeNA, GREE and mixi are the biggest social players in Japan and there are thousands of social game companies in Tokyo. Twitter has reached my local friends and its continuos growth looks promising. Few local friends have facebook accounts and start seeing more, but people seem not getting how they can use facebook.
One of the key points in Japan is that "keitai" is still a dominant way to access web services for most of people. I've never seen my local friends have laptops at home or my sister using the Internet at home. Keitai is everything and that's all you need for daily use (such as music, transportation guide, news, and games etc). The last year, Smartphones Account For 50% Of Current Handset Sales in Japan. It is a dramatic shift and I believe this growth will continue, knowing more localized (having Japanese keitai features like Osaifu-Keitai and Suica-support) Android phones are coming this year. But I did not see many smartphone users in non-Tokyo area and some people have strong bias towards Galakei.
One of geographic features of Tokyo is its condense population. When some people sense a "next trend" and start spreading words, it explodes pretty quickly and all they talk about is that topic. I think this is happening in social media and social games.
It is always interesting to see what is happening in Tokyo. I look forward to visiting there again.