It is important to understand the linguistic intricacies of Hong Kong where English, Traditional Chinese and sometimes Simplified Chinese are used interchangeably across different search engines. Don't be fooled by the thought of many that English alone is the core of all activity.
The search landscape is split almost evenly between Yahoo/Bing Alliance and Google and it's strongly recommended to utilise both engines to maximise coverage. Yahoo Hong Kong offers Sponsored Direct Display, which places the ad under the paid ads but above organic results. This offers brand protection, promotes your products and given its position, typically has strong click through rates.