Three Essays On Networks And Public Economics

This thesis is a collection of three essays. The first two study how ideas spread through a network of individuals, and how it an advertiser can exploit it. In the model I develop, users choose their sources of information based on the perceived usefulness of their sources of information. This contrasts with previous literature where there is no choice made by network users and thus, the information flow is fixed. I provide a complete theoretical characterization of the solution and define a natural measure of influence based on choices of users. I also present an algorithm to solve the model in polynomial time on any network, regardless of the scale or the topology. I also discuss the properties of a network technology from a public economic standpoint. In essence, a network allows the reproduction of ideas for free for the advertiser. If there is any free-riding problem, I show that coalitions of users on the network can solve such problem. I also discuss the social value of networks, a value that cannot be captured for profit. The third essay is completely distinct from the network paradigm and instead studies funding rules for public universities. I show that a funding rule that depends solely on enrolment leads to "competition by franchise" and that such behavior is sometimes inefficient. I suggest instead an alternate funding rule that allows government to increase welfare without increasing spending in universities.