Carousel Ads Optimization in Yahoo Gemini Native

Yahoo's native advertising (also known as Gemini native) serves billions of ad impressions daily, reaching a yearly run-rate of many hundred of millions USD. Driving Gemini native models for predicting both click probability (pCTR) and conversion probability (pCONV) is OFFSET - a feature enhanced collaborative-filtering (CF) based event prediction algorithm. The predicted pCTRs are then used in Gemini native auctions to determine which ads to present for each serving event. A fast growing segment of Gemini native is Carousel ads that include several cards (or assets) which are used to populate several slots within the ad. Since Carousel ad slots are not symmetrical and some are more conspicuous than others, it is beneficial to render assets to slots in a way that maximizes revenue. In this work we present a post-auction successive elimination based approach for ranking assets according to their click trough rate (CTR) and render the carousel accordingly, placing higher CTR assets in more conspicuous slots. After a successful online bucket showing 8.6% CTR and 4.3% CPM (or revenue) lifts over a control bucket that uses predefined advertisers assets-to-slots mapping, the carousel asset optimization (CAO) system was pushed to production and is serving all Gemini native traffic since. A few months after CAO deployment, we have already measured an almost 40% increase in carousel ads revenue. Moreover, the entire revenue growth is related to CAO traffic increase due to additional advertiser demand, which demonstrates a high advertisers' satisfaction of the product.