This document provides an introduction to online advertising and search engine marketing. It discusses how global digital ad spending is projected to surpass newspaper advertising by 2015. It defines different types of online advertising including search engine marketing, display ads, email marketing and mobile ads. It specifically focuses on search engine marketing and pay-per-click advertising. It lists many popular global search engines and explains why Google is a good choice for search engine marketing due to its large user base and constantly improving search algorithms.