Real-time Ad retrieval via LLM-generative Commercial Intention for Sponsored Search Advertising
Tongtong Liu, Zhaohui Wang, Meiyue Qin, Zenghui Lu, Xudong Chen, Yuekui Yang, Peng Shu
TL;DR
This paper tackles real-time sponsored-search ad retrieval by replacing heavy DocIDs with LLM-generated Commercial Intentions (CIs) as semantic tokens. It introduces RARE, an end-to-end architecture featuring knowledge-injected, format-finetuned LLMs, a CI-Ads inverted index, and constrained decoding plus caching to achieve millisecond-scale real-time retrieval. Online deployment across large-scale systems yields meaningful gains in consumption, GMV, CTR, and conversions, while offline experiments show superiority over multiple baselines in HR@500, MAP, and ACR. The work demonstrates the practical viability of using generated commercial intents to bridge queries and ads at scale, with robust ablations and real-world online validation supporting its effectiveness.
Abstract
The integration of Large Language Models (LLMs) with retrieval systems has shown promising potential in retrieving documents (docs) or advertisements (ads) for a given query. Existing LLM-based retrieval methods generate numeric or content-based DocIDs to retrieve docs/ads. However, the one-to-few mapping between numeric IDs and docs, along with the time-consuming content extraction, leads to semantic inefficiency and limits scalability in large-scale corpora. In this paper, we propose the Real-time Ad REtrieval (RARE) framework, which leverages LLM-generated text called Commercial Intentions (CIs) as an intermediate semantic representation to directly retrieve ads for queries in real-time. These CIs are generated by a customized LLM injected with commercial knowledge, enhancing its domain relevance. Each CI corresponds to multiple ads, yielding a lightweight and scalable set of CIs. RARE has been implemented in a real-world online system, handling daily search volumes in the hundreds of millions. The online implementation has yielded significant benefits: a 5.04% increase in consumption, a 6.37% rise in Gross Merchandise Volume (GMV), a 1.28% enhancement in click-through rate (CTR) and a 5.29% increase in shallow conversions. Extensive offline experiments show RARE's superiority over ten competitive baselines in four major categories.
