Biases in online platforms pose a threat to social inclusion. I examine the influence of social biases on online platforms. In my dissertation, I conduct empirical studies on online crowdfunding platforms (prosocial lending and educational crowdfunding) to investigate the influence of funders' or recipients' social backgrounds on the funding dynamics. In the first study, I examine the influence of a novel source of bias in online philanthropic lending, namely that associated with religious differences. I further propose a set of contextual moderators that characterize individuals’ offline (local) and online social contexts, which I argue combine to determine the influence of religion distance on lending activity. In the second study, I theoretically and empirically explore the role of value homophily in shifting lending priorities in online pro-social platforms. Considering the full spectrum of cultural influences, I develop the concept of “culturalist choice homophily,” where value-based similarities emerge based on the culturally-motivated behaviors and “historicist choice homophily,” where value-based similarities emerge based on similarities in historical-cultural barriers. Further, I introduce a novel content-context value congruence perspective for crisis fundraising, where the synergy between a borrowers’ request reasoning and the optimal crisis outcome determines the volume of lending received by crisis victims. I utilize the Arab Spring crisis in a Difference-in-Difference (DID) setting to test my hypotheses. Finally, in the third study, I add to the recent literature on the impact of the design of educational crowdfunding in alleviating inequality for public schools' fundraising. I particularly explore the effects of the platform intervention in terms of signaling students’ need to alleviate biases toward racially and economically disadvantaged students. Utilizing data from DonorsChoose.org, I first show that the online platform cannot automatically make up for all biases, especially toward classrooms with students with a higher level of poverty or racially marginalized communities. Further, I show that labeling projects as equity-focus can alleviate biases. However, the results are heterogeneous across different sources of identity. In particular, I discuss that equity-focus labeling has a greater impact on improving inequality toward hard-to-observe identities, e.g., economically disadvantaged students, than easy-to-observe identities such as racially underprivileged communities.

Various activities move online in the era of the digital economy. Platform design and policy can heavily affect online user activities and result in many expected and unexpected consequences. In this dissertation, I conduct empirical studies on three types of online platforms to investigate the influence of their platform policy on their user engagement and associated outcomes. Specifically, in Study 1, I focus on goal-directed platforms and study how the introduction of the mobile channel affects users’ goal pursuit engagement and persistence. In Study 2, I focus on social media and online communities. I study the introduction of machine-powered platform regulation and its impacts on volunteer moderators’ engagement. In Study 3, I focus on online political discourse forums and examine the role of identity declaration in user participation and polarization in the subsequent political discourse. Overall, my results highlight how various platform policies shape user behavior. Implications on multi-channel adoption, human-machine collaborative platform governance, and online political polarization research are discussed.