The Russians and Chinese are no doubt frontrunners on IDN implementation. The Japanese are cueing up, and will be aliasing idn.jp to idn.idn based on recent info put out on DNAME by the Japanese Registry. If you have idn.cn, viewing the internet inside China the .cn is in Chinese now and you basically get 2:1 since you get both Simplified Chinese domain AND the Traditional Chinese equivalent.
idn.cn = idn.ä¸å½ = idn.ä¸å
The Russians are rolling out idn.ÑÑ starting this fall to huge media fanfare. There is significant traffic to idn.com that kicked in as the media started the new stories about idn.idn. In addition, 20% of Russian internet users have Opera browers which automatically defaults "type-in" to idn.com.
Worth the read is a new IDN blog with a good article and update on the happenings with Russian IDNs. If you are a domainer looking for some potential opportunities that potentially have a high ROI, this might be worth a read and then make up your own mind.
http://www.idndemystified.com/