1. A method comprising: receiving a request for a predetermined number of advertisements in response to a user submitting a search query on a host site, the host site hosting a plurality of listings of items for sale; obtaining a set of candidate advertisements; obtaining for each of the set of candidate advertisements a respective advertiser quality score pre-calculated in an automated non-realtime operation prior to user-submission of the search query, the respective advertiser quality scores being based at least in part on one or more factors from the group consisting of: advertiser revenue volume and advertiser seniority; obtaining for each of the set of candidate advertisements a respective advertisement quality score pre-calculated in an automated non-realtime operation prior to user-submission of the search query; in an automated operation performed using one or more computer processors configured to perform the operation, excluding from the set of candidate advertisements each advertisement that fails to satisfy a preliminary inclusion criterion, thereby obtaining a plurality of advertisements for further consideration, the preliminary inclusion criterion comprising at least one of: the corresponding advertiser quality score equaling or exceeding a predefined advertiser quality score threshold, and the corresponding advertisement quality score equaling or exceeding a predefined advertisement quality score threshold; for each advertisement in the plurality of advertisements, identifying a set of features corresponding to items of the advertisement; obtaining personalized consumer profile data including data indicative of a search and transaction history of a plurality of users; for each advertisement in the plurality of advertisements, obtaining context data including associations between the personalized consumer profile data and the set of features corresponding to items of the advertisement; for each advertisement in the plurality of advertisements, generating, by use of a processor, a predicted click through rate (CTR) corresponding to the advertisement based in part on the set of features corresponding to items of the advertisement, the personalized consumer profile data, and the context data; thereafter automatically calculating, by use of at least one computer processor device configured therefor, a respective predicted yield for each of the plurality of advertisements, the calculating of the predicted yield for each of the plurality of advertisements comprising combining the corresponding click through rate, the corresponding advertiser quality score the corresponding advertisement quality score, and a corresponding cost per click payable by an associated advertiser; ranking, by use of the processor, the plurality of advertisements based on their corresponding predicted yields; selecting, by an advertising optimization engine implemented on an advertising optimization server, the predetermined number of advertisements based on the ranking; and causing the selected advertisements to be displayed on the host site concurrently with search results for the search query, the search results comprising a portion of the plurality of listings of items for sale.