Ken told me that ChinesePod has exploded in popularity over the past year - it's had approximately 10 million lesson downloads and currently occupies a prominent position in places like Yahoo Podcasts.

Visiting the ChinesePod site is a pleasure, as it is very well designed and a visual treat. And the business model is surprisingly simple - subscriptions to language-learning materials. This complements the free offerings - basically, the Mandarin podcasts - very nicely. For example, if you want to dive into learning Mandarin straight away: select one of the episodes, plus you can participate in the discussions. The first level subscription is called 'Basic' and gets you a PDF transcript of the podcast. If you want get really serious about learning Mandarin, sign up to the premium subscription service and receive learning resources such as Review Materials and Lesson Plans.

I think ChinesePod beautifully illustrates how you can run a small, niche - but successful and moneymaking - business on the Web. ChinesePod offers enough free material to make it worthwhile for the casual visitor, but offers real value too if you're willing to pay a subscription fee for tools and resources that help you learn Mandarin.

The community aspect of ChinesePod also shows what can be done with read/write Web technologies. Check out the Community page - which has a forum, wiki, blogs, photos, rss feeds. All the usual pieces, but what I like about it is that each has a practical purpose. The wiki has extra links and information, the forum is well-used by users, the photos are lovely (of China), and there are a lot of great rss feeds to choose from.

Unfortunately I don't have time to learn Mandarin right now, but if I did ChinesePod would be my first port of call.