The Ordered Timeline Game: Strategic Posting Times Over a Temporally Ordered Shared Medium

We consider a game of timing between a random number of content creators, who compete for position and exposure time over an ordered shared medium such as an online classified list. Contents (such as ads, messages, multimedia items, or comments) are ordered according to their submission times, with more recent submissions displayed at the top (and better) positions. The instantaneous effectiveness of each item depends on its current display position, as well as on a time-dependent site exposure function which is common to all. Each content creator may choose the submission time of his or her item within a finite time interval, with the goal of maximizing the total exposure of this item. We formulate the problem as a noncooperative game and analyze its symmetric Nash equilibrium. We show existence of the equilibrium profile, characterize it in terms of a differential boundary value problem, provide sufficient conditions for its uniqueness, and devise a numerical scheme for its computation. We further compute the equilibrium profile explicitly for certain special cases, which include a two-player small match and a Poisson-distributed number of players, and evaluate the social efficiency of these equilibria.