Microsoft will be in charge of self-service sales of pay-per-click text search ads.
2
Google makes most of its revenue from pay-per-click search ads.
3
Search engine marketing (SEM) is the process of using natural search engine optimization (SEO) and pay-per-click (PPC) advertising to increase the visibility of your website.
4
Google's Pay-Per-Click AdWords system matches ads based on an individual's exact search terms.