Byline: Changjun Lee [email@example.com] (a,*), Junseok Hwang [firstname.lastname@example.org] (b,1) Keywords Content diversity; Platform ecosystem; Giant platform; Genetic algorithm; Industry dynamics Highlights * Expansion of platform do reduce the internal content diversity * High content diversity increases in innovation capacity of the platform ecosystem. * Retaining their uniqueness of content is positively correlated with content diversity. * Users' will to find other sources of content recovers decreased content diversity. Abstract Scholars have studied how giant platforms influence on the innovation ecosystem as platform providers (PPs) has grown in large size because of their unique and necessary position in the ICT ecosystem. To find the influence of giant PPs' market power on diversity of CPs and the role of content diversity in the innovation ecosystem, we modeled the platform ecosystem and examined the effect of a PP's expansion on various outcomes by using a simulation model based on genetic algorithm. Results show that, firstly, a PP's expansion do reduce the internal content diversity, secondly, high content diversity influences on increasing in innovation capacity of the platform ecosystem, thirdly, the ratio of CPs that retain their uniqueness of content is positively correlated with content diversity, and lastly, the users' will to find alternative sources of content aids in the recovery of decreased content diversity. This might contribute for policy makers and stakeholders in the platform ecosystem to understand the overall picture of the industry dynamics and the innovation strategy in ecological perspective. Author Affiliation: (a) Lee Kuan Yew School of Public Policy, National University of Singapore, Singapore (b) Technology of Management, Economics and Policy Program, Seoul National University, Seoul, South Korea * Corresponding author at: Lee Kuan Yew School of Public Policy, National University of Singapore, 469C Bukit Timah Road, Oei Tiong Ham Building, 259772, Singapore. Article History: Received 29 December 2015; Revised 13 July 2016; Accepted 29 November 2016 (footnote)1 Postal address: Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 151-742, South Korea.