Recent claims that online platforms have secured permanent monopolies, protected by barriers to entry from network effects and stockpiles of data, and should be the focus of intense antitrust and regulatory scrutiny, are inconsistent with the economics, technology, and history of online...

This article provides an overview of the competitive issues surrounding online platforms. The general theme is that while much has been made of the structural features of online platforms there is little hard evidence that these are durable monopolies. Nonetheless, there are concerns about the...

When a consumer can appear on both sides of a two-sided market, such as a user who both buys and sells on eBay, the platform may want to bundle the services it provides to two sides. I develop a general model for such "mixed" two-sided markets, and show that a monopolist platform's incentive to...

Successful platforms attract not just many users, but also those of the right kind. "The right kind of user" is one who can either be directly monetized or who differentially attracts other valuable users. Bonacich centrality on the network of user sorting with direct value of monetization...

I model dynamic product design along price and non-price dimensions by a firm in a market with positive network externalities between consumers. In the case of a usage fee, I provide conditions under which the steady state (SS) is unique and show that the introductory price is negative and...

We study the welfare effects of a merger between ad-funded platforms facing elastic consumer demand. We show that advertising fees as well as quality investment levels by the platforms fall post-merger. Interestingly, despite the lower advertising fees, advertisers may be worse off when their...

Dominant or apparently dominant internet platform increasingly become subject to both antitrust investigations and further-reaching political calls for regulation. While Google is currently in the focus of the discussion, the next candidate is already on the horizon - the ubiquitous online...

Should the FTC have allowed Zillow to acquire its foremost rival, Trulia? It is increasingly well-accepted that digital platforms tend toward dominance in their immediately adjacent relevant-product markets. Google, for example, has long held a majority share of the markets for general-search...

Many online businesses, including most of the largest platforms, seek and provide attention. These online attention rivals provide products and features to obtain the attention of consumers and sell some of that attention, through other products and services, to merchants, developers and others...

This paper shows that two related aspects of attention platforms are important for the sound economic analysis of public policy including antitrust: First, attention platforms generate valuable content. Even though people often don't pay for content, we know from revealed preference that content...