Abstract: Crowdfunding, a new internet financing mode, has undergone rapid development since it arises in China and has a thriving prospect in the long run. For the purpose of attracting numerously potential investors to participate this financing activity, initiator seeks to utilize many methods, including the degree of project dynamic update and adverse incentive, to enhance the popularity of crowdfunding project. However, there is lack of a special marketing mode based on social network in the process of propagandistic crowdfunding project. In order to explore the acceleration effect of social network marketing in existing crowdfunding mode, three crowdfunding mechanisms are raised where an initiator advertises his financing project through social network compared with traditional crowdfunding publicity relied on crowdfunding platform merely, meanwhile, considering to put social network publicity into the different period of crowdfunding. Further, the total purchase function with demand depending on price and the publicity degree of social network under three modes is investigated based on the hypothesis of Homo Economicus, and the revenue model is built based on the dynamic games of complete information theory. Finally, the equilibrium results of non-social network marketing and existing social network publicity in crowdfunding activity are discussed based on revenue maximization and Stackelberg game. The equilibrium results signify when the social comprehensive cost is higher, the "social-crowdfunding" mode can achieve the increasement of net financing amount if the social enhancement coefficient is high enough and the minimum cost restriction requested by social platform is relatively low. But the "crowdfunding-social-crowdfunding" mode can achieve a higher financing amount compared with the "social-crowdfunding" mechanism in any situation. Additionally, the crowdfunding price of product and the advertising degree on the social network are both higher in cooperation case. In conclusion, through analyzing and contrasting different financing mechanism and illustrating the presented cases of social crowdfunding, it is concluded that the marketing incentive of social network is completely necessary in emerging crowdfunding market. In brief, theoretical basis and practical gist for exploring and optimizing the social mechanism in crowdfunding project are provided in this paper.

Key words: social network, platform push, product crowdfunding, game theory