We've mentioned before that Apple has big plans to sell devices and computers in emerging markets such as China, but this year's WWDC has moved the plan from Apple selling hardware to its developers trying to sell apps as well. If you saw the keynote on Monday, you probably noticed that Tim Cook and co. pushed hard to convince developers that China was the next big market in apps. There are a number of new features coming to both Mountain Lion and iOS 6 that are aimed directly at Chinese users.
Most of it so far is supporting Chinese services, such as search engine Baidu and the extremely popular microblogging (sort of like Twitter) service Sina Weibo. Text input is another big area that Apple has been working on with its software, and Siri has been updated to work with a few more Chinese dialects. On the OS X side, Mail has gotten an update to work with QQ Mail and a few other popular Chinese email services.
This is likely only the beginning of more and more Apple support for China and its users. Given how the market over there is growing, Apple is investing heavily in that area going forward.