For the next 9-12 months (or possibly longer) I will be based in Japan. I will head up our new project for a Japanese client and also set up our local office here. Talk about the flat world: I'm a Korean guy educated in the US, who was mostly working with European folks in his previous job, and is now working in Japan.
One thing I noticed about Japan almost instantly was diversity. I think one of the huge misconceptions about Japan from the outside world is that the country is very homogeneous. Diversity means, among other things, the "long tail economy" flourishes here: Around every corner of Japanese streets you can find local "mom and pop" shops that have been there for generations. Bookstores are full of narrowly targeted magazines for the Ottakus, or people with very focused interest in a specific field. I found "Old Mac" magazine to help you renovate your old Mac G3's case, and "Google Earth" magazine with tips to use Google Earth more wisely.
I think this high level of diversity is one of the reasons why Japan doesn't have a single web service that's being used by a predominant portion of the population (such as Cyworld of Korea, which is used by 90% of Korean twenty-somethings). Mixi, the #1 social networking site, has around 9 million subscribers, less than 7% of the country's population. So this means: if you are a foreign web entrepreneur determined to take over the Japanese market with your web service, hoping to become the Myspace of Japan, well, you better think twice. That's very unlikely to happen here, even for local Japanese companies. The best shot you have is to become the Myspace of a specific group of Japanese people.
These are some of my initial observations about Japan and its web/mobile market. I'll definitely write more about them as I get myself acquainted in this bustling yet calm country. Obviously I'll also keep myself posted on Korean web innovations and write about them as well.