The longest second: Header bidding and the material politics of online advertising

Abstract A user’s online action is often followed, around a second later, by ads being shown to her/him. Much happens in that second, including near-instantaneous auctions (sometimes coordinated by the user’s own phone or other device) in which algorithms bid to show particular advertisers’ ads. Contributing to the burgeoning social-science literature on online advertising, we examine contending material forms these auctions take in ‘open display’ advertising. We trace the emergence of Google’s centralized auctions, and how they have been challenged by decentralized ‘header bidding’. We argue: first, that ad platforms should be seen as ‘stack economization’ processes, which layer different forms of economization in complex ways; second, that those processes are sometimes fiercely contested, and can be the site of intricate – and currently changing – material politics.