Japan has recently
overtaken South Korea as the most wired country. I think Korea might still have the highest broadband saturation (I understand it's around 75% of households that have broadband ... which is pretty stunning given that 60 years ago Korea was the poorest country on the planet). Somewhere, I also read that Chinese people spend the most amount of time online, on average.
I never lived in Japan or China, but I have lived in South Korea, and Korea is an interesting study in internet technology and its ramifications on the culture and economy. Cyworld minihompis are what myspace hopes to be, except they
don't suck like Myspace does. Text messaging is far and away the fastest, easiest way to communicate and it's typically free there. Cellphones work on the subways, which was a huge shock to me, and they're pretty much all web-enabled. Internet cafes are everywhere and cheap (about a dollar an hour), and even girls play games online. As a web developer, it's exciting for me to see a country that so embraces the internet and has figured out ways to make it work for them. They also have kickass food, soju is great after the 1st or 2nd shot but gives the drinker an almost unholy need to sing at noraebang, and the people are awesome if you speak Korean to them. The local beer sucks, though (Hite is pretty bad, you have to admit).