This study will separate into two phases. Phase I is a large scale cross-sectional survey to corporations in Hong Kong to examine the employers' knowledge, attitudes and practices in promoting smoking cessation in the workplace. Phase II is a longitudinal randomized controlled trial study to evaluate the effectiveness of a smoking cessation intervention to assess the subjects' smoking behaviors, knowledge on smoking and satisfaction of the smoking cessation services. The investigators are interested to know if the intervention package including health education,social media and telephone follow-up would trigger higher quit rate or other changes in smoking behaviors. The investigators will also monitor the smoking status of the subjects regularly through telephone follow-ups, understand the company's practices about smoke-free policy as well as evaluate the outcomes of the intervention.