This document discusses online advertising. It begins with facts about click-through rates and reactions to autoplay videos. It then defines common online advertising idioms and lists some major advertising platforms. The advantages of online ads are listed as fast results, measurable performance, independence from search engine algorithms, ability to target audiences, brand recognition, cost-effectiveness, and reporting capabilities. Finally, the major types of online ads are identified as display, social media, search, native, retargeting, video, and email ads.