I assume ditu is maps in Chinese? :-)
Based on the thread, it appears that:
- City detail is very limited
- Major roads are available
- Cities like Shanghai and Beijing have more detail than others
- Suspicions that this map service is powered directly from a 3rd party source, possibly mapgoogle.mapabc.com.
- The main Google Maps has more details on Hong Kong then this China version
Forum discussion at WebmasterWorld.