  Payments in online ad auctions are typically derived from click-through
rates, so that advertisers do not pay for ineffective ads. But advertisers
often care about more than just clicks. That is, for example, if they aim to
raise brand awareness or visibility. There is thus an opportunity to devise a
more effective ad pricing paradigm, in which ads are paid only if they are
actually noticed. This article contributes a novel auction format based on a
pay-per-attention (PPA) scheme. We show that the PPA auction inherits the
desirable properties (strategy-proofness and efficiency) as its
pay-per-impression and pay-per-click counterparts, and that it also compares
favourably in terms of revenues. To make the PPA format feasible, we also
contribute a scalable diagnostic technology to predict user attention to ads in
sponsored search using raw mouse cursor coordinates only, regardless of the
page content and structure. We use the user attention predictions in numerical
simulations to evaluate the PPA auction scheme. Our results show that, in
relevant economic settings, the PPA revenues would be strictly higher than the
existing auction payment schemes.
