Firstly - Why do I have to register to use? It would be nice to specify your language and jump in. Then if I enjoy the experience, I can sign up with my e-mail address, etc.
Secondly - Having spent a bit of time around Asia, the market to learn English is absolutely huge! A lot of people are desperate to practise English with a native speaker. In Taiwan, sometimes had people (usually high school kids) coming up to me in the street wanting to practise. However it will require localised sites, written in Chinese, or Korean or Japanese to tap this market. Also, it will need a different marketing strategy to what you might use for English, or a European market. In China for example, a lot of people spend most of their time hanging around on BBS's like MOP. For obvious reasons using Google ad-words would be a no go ...