JUNE 18, 2010 • While Twitter first arrived in Japan during 2008, the service really took off last October after a mobile version was released. Now 16.3% of Japanese Internet users Tweet, according to Nielsen Online. That’s compared to 9.8% percent in the U.S. Twitter far outpaces Facebook in Japan, with the latter garnering only 3% of Internet users in the country. The Japanese translation of tweeting is mumbling.

Impact: Twitter’s success in Japan tells us that there is a huge opportunity for mobile-based social networks there. We also think that whoever gets to those mobiles with a cute, truly multiplayer social network micro-transaction game will make a mint.