Invite your friends and get rewards: dynamics of incentivized friend invitation in kakaotalk mobile games

Incentivized friend invitation is an efficient and effective user growth mechanism, more so when combined with social platforms, such as online social networks (OSNs) or mobile instant messengers (MIMs). KakaoGame, a two-year-old mobile game platform based on a dominant MIM called KakaoTalk, brought 5.2 billion sign-ups over 520 games with quota-based reward schemes. How does the reward scheme help the spread of services? In this paper, we analyze the friend invitation logs from 4 mobile games on KakaoGame, consisting of 330 million invitations from 8.4 million users to 36 million users. Our analysis aims at answering the following three key questions. (a) How do quota-based reward schemes stimulate invitation behavior? (b) How many invitations trigger the invitee to sign up for the game or become an annoyance to make the invitee turn a blind eye? (c) How fast are the invitations sent out and how does the diffusion slow down? Based on the analysis, we provide practical insights for viral marketing.