In sponsored search advertising (SSA), keywords serve as the basic unit of business model, linking three stakeholders: consumers, advertisers and search engines. This paper presents an overarching framework for keyword decisions that highlights the touchpoints in search advertising management, including four levels of keyword decisions, i.e., domain-specific keyword pool generation, keyword targeting, keyword assignment and grouping, and keyword adjustment. Using this framework, we review the state-of-the-art research literature on keyword decisions with respect to techniques, input features and evaluation metrics. Finally, we discuss evolving issues and identify potential gaps that exist in the literature and outline novel research perspectives for future exploration.

翻译：在赞助搜索广告中，关键词作为商业模式的基本单位，连接着消费者、广告商和搜索引擎三方利益相关者。本文提出了一个涵盖关键词决策的总体框架，突出搜索广告管理中的关键接触点，包括四个层次的关键词决策：领域特定关键词池生成、关键词定向、关键词分配与分组以及关键词调整。利用该框架，我们综述了关于关键词决策的最新研究文献，涉及技术、输入特征和评估指标。最后，探讨了不断演变的问题，识别了文献中存在的潜在空白，并概述了未来探索的新研究视角。