  Viral marketing is different from other marketing strategies since it
leverages the influence power in intimate relationship, e.g., close friends,
family members, couples. Due to the development and popularity of social
networking services, such as Facebook, Twitter, and Pinterest, the new notion
of "social media marketing" has appeared in recent years and presents new
opportunities for enabling large-scale and prevalent viral marketing online. To
boost the growth of their sales, business is embracing social media in a big
way. According to USA Today, the sales of software to run corporate social
networks will grow 61\% a year and be a $6.4$ billion business by 2016.
