Paid search is the practice of bidding on keywords to display ads at the top of search engine results pages. Ad formats include text, responsive, and shopping ads, with users signaling active intent by typing a query and pricing set in real time by auction (max bid multiplied by Quality Score equivalent). It is the workhorse of paid acquisition for any business whose customers actively search for what they sell, and the channel where intent signals are richest.
The two major platforms by spend are Google Ads (running on Google Search, Search Partners, and Google Shopping) and Microsoft Ads (running on Bing, Yahoo, AOL, and DuckDuckGo via their partnership). Google holds roughly 83 percent of global search market share in 2025, w...