关键词广告是一种文本链接型网络广告，当用户以某关键词在搜索引擎上进行搜索时，在结果页面的固定位置会出现与该关键词相关的广告链接。

Keyword advertising is a form of online advertising in which an advertiser pays to have an advertisement appear in the results listing when a person uses a particular phrase to search the Web, typically by employing a search engine. The particular phrase is composed of one or more keyterms that is linked to one or more advertisements. The most common form or keyword advertising, focused on payment methods, is pay per click (PPC), with other forms being cost per action (CPA) or cost per mille (CPM).