While page views are often sold instantly through real-time auctions when users visit websites, they can also be sold in advance via guaranteed contracts. In this paper, we present a dynamic programming model to study how an online publisher should optimally allocate and price page views between guaranteed and spot markets. The problem is challenging because the allocation and pricing of guaranteed contracts affect advertisers' purchase between the two markets, and the terminal value of the model is endogenously determined by the updated dual force of supply and demand in auctions. We take the advertisers' purchasing behaviour into consideration, i.e., risk aversion and stochastic demand arrivals, and present a scalable and efficient algorithm for the optimal solution. The model is also empirically validated with a commercial dataset. The experimental results show that selling page views via both guaranteed contracts and auctions can increase the publisher's expected total revenue, and the optimal pricing and allocation strategies are robust to different market and advertiser types.
Guaranteed contract pricing has also been discussed in several recent studies. @cite_22 presented two algorithms to compute the price of a guaranteed contract based on the statistics of users' visits to the web pages. @cite_19 and @cite_20 used queueing systems and discussed two different pricing schemes for a publisher who promises to deliver a certain number of clicks or impressions on the ads posted, where uncertain demand, traffic and click behaviour are considered. @cite_10 , @cite_8 and @cite_4 discussed several pricing methods for various flexible guaranteed contracts tailored to display advertising, called ad options. The ideas came from financial and real options . Simply, if an advertiser pays a small fee to buy an ad option, he is guaranteed a priority buying right but not an obligation of his targeted future impressions. He can then decide to pay the fixed price in the future to advertise.
@cite_4 @cite_22 @cite_8 @cite_19 @cite_10 @cite_20
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We consider the problem of pricing guaranteed contracts in online display advertising. This problem has two key characteristics that when taken together distinguish it from related offline and online pricing problems: (1) the guaranteed contracts are sold months in advance, and at various points in time, and (2) the inventory that is sold to guaranteed contracts - user visits - is very high-dimensional, having hundreds of possible attributes, and advertisers can potentially buy any of the very large number (many trillions) of combinations of these attributes. Consequently, traditional pricing methods such as real-time or combinatorial auctions, or optimization-based pricing based on self- and cross-elasticities are not directly applicable to this problem. We hence propose a new pricing method, whereby the price of a guaranteed contract is computed based on the prices of the individual user visits that the contract is expected to get. The price of each individual user visit is in turn computed using historical sales prices that are negotiated between a sales person and an advertiser, and we propose two different variants in this context. Our evaluation using real guaranteed contracts shows that the proposed pricing method is accurate in the sense that it can effectively predict the prices of other (out-of-sample) historical contracts. There are two major ways of selling impressions in display advertising. They are either sold in spot through auction mechanisms or in advance via guaranteed contracts. The former has achieved a significant automation via real-time bidding (RTB); however, the latter is still mainly done over the counter through direct sales. This paper proposes a mathematical model that allocates and prices the future impressions between real-time auctions and guaranteed contracts. Under conventional economic assumptions, our model shows that the two ways can be seamless combined programmatically and the publisher's revenue can be maximized via price discrimination and optimal allocation. We consider advertisers are risk-averse, and they would be willing to purchase guaranteed impressions if the total costs are less than their private values. We also consider that an advertiser's purchase behavior can be affected by both the guaranteed price and the time interval between the purchase time and the impression delivery date. Our solution suggests an optimal percentage of future impressions to sell in advance and provides an explicit formula to calculate at what prices to sell. We find that the optimal guaranteed prices are dynamic and are non-decreasing over time. We evaluate our method with RTB datasets and find that the model adopts different strategies in allocation and pricing according to the level of competition. From the experiments we find that, in a less competitive market, lower prices of the guaranteed contracts will encourage the purchase in advance and the revenue gain is mainly contributed by the increased competition in future RTB. In a highly competitive market, advertisers are more willing to purchase the guaranteed contracts and thus higher prices are expected. The revenue gain is largely contributed by the guaranteed selling. Display advertising has traditionally been sold via guaranteed contracts --- a guaranteed contract is a deal between a publisher and an advertiser to allocate a certain number of impressions over a certain period, for a pre-specified price per impression. However, as spot markets for display ads, such as the RightMedia Exchange, have grown in prominence, the selection of advertisements to show on a given page is increasingly being chosen based on price, using an auction. As the number of participants in the exchange grows, the price of an impressions becomes a signal of its value. This correlation between price and value means that a seller implementing the contract through bidding should offer the contract buyer a range of prices, and not just the cheapest impressions necessary to fulfill its demand. Implementing a contract using a range of prices, is akin to creating a mutual fund of advertising impressions, and requires randomized bidding. We characterize what allocations can be implemented with randomized bidding, namely those where the desired share obtained at each price is a non-increasing function of price. In addition, we provide a full characterization of when a set of campaigns are compatible and how to implement them with randomized bidding strategies. Display advertising has traditionally been sold via guaranteed contracts -- a guaranteed contract is a deal between a publisher and an advertiser to allocate a certain number of impressions over a certain period, for a pre-specified price per impression. However, as spot markets for display ads, such as the RightMedia Exchange, have grown in prominence, the selection of advertisements to show on a given page is increasingly being chosen based on price, using an auction. As the number of participants in the exchange grows, the price of an impressions becomes a signal of its value. This correlation between price and value means that a seller implementing the contract through bidding should offer the contract buyer a range of prices, and not just the cheapest impressions necessary to fulfill its demand. Implementing a contract using a range of prices, is akin to creating a mutual fund of advertising impressions, and requires randomized bidding . We characterize what allocations can be implemented with randomized bidding, namely those where the desired share obtained at each price is a non-increasing function of price. In addition, we provide a full characterization of when a set of campaigns are compatible and how to implement them with randomized bidding strategies.