Abstract: A dynamic mechanism for selling online advertising space may involve computing allocation rules and pricing structures to align incentives of seller and bidders. Based on initial valuations reported by multiple advertisers, an advertising platform may compute entrance fees to be charged to each advertiser who enters into a contract for allocation of an advertising space over multiple allocation cycles. Based on an initial valuation reported by an advertiser, an advertising platform may compute an entrance fee to be charged to the advertiser as a lump sum or subscription fee, determine whether to allocate the advertising space to the advertiser in multiple successive allocation cycles, and compute allocation payment amounts to be charged to the advertiser when the advertiser receives allocations. Through appropriate construction of these computations, incentives may be aligned such that advertisers benefit from truthful reporting of valuations.