This online appendix to "Insulated Platform Competition" includes proofs and details of our applications.The paper to which these Appendices apply is available at the following URL: "http://ssrn.com/abstract=1694317" http://ssrn.com/abstract=1694317

We review the economics of superstars, originally developed for stars in traditional media, and discuss whether they are applicable for the (allegedly) novel phenomenon of stars in social media (influencer, micro-celebrities). Moreover, we analyse potentially new factors for creating social...

The paper applies economic theories to give an overview of the emerging phenomenon of digital personal assistants (DPAs). A DPA is an intelligent automated system that interacts with the user through a dialogue in natural language, and meanwhile applying third-party services to obtain...

We extend the theory of tax incidence under Cournot-Nash oligopolistic competition to study the effects of an ad valorem sales tax on Web services (so-called Web Tax) that are provided free of charge to users, and produce advertising space sold to businesses. Ads are more valuable to advertisers...

We review the economics of superstars, originally developed for stars in traditional media, and discuss whether they are applicable for the (allegedly) novel phenomenon of stars in social media (influencer, micro-celebrities). Moreover, we analyse potentially new factors for creating social...

We analyze platform competition where user data is collected to improve adtargeting. Considering that users incur privacy costs, we show that the equilibrium level of data provision is distorted and can be inefficiently high or low: if overall competition is weak or if targeting benefits are...

In this note I examine price competition between two sellers who sequentially arrive to an online consumer-to-consumer market (e.g., Craigslist). Each seller has one unit of a homogeneous good that they want to sell to a pool of buyers. When buyers arrive randomly to the market, I show that...

This chapter provides an overview of the economics of influencers and social media stardom. It provides the state-of-research regarding success factors, revenue and payment models, social media platforms and ecosystems, and welfare effects. It describes the role of social media content providers...

We build a model of the news market where advertisers allocate their ads between a social media platform and a news website. Our objective is to evaluate policy interventions aimed at fostering news creation by transferring revenues from social media to news websites already introduced in...