Search Engine Marketing
Search engine marketing, or SEM, is a form of Internet marketing that seeks to promote websites by increasing their visibility in search engine result pages (SERPs).
According to the Search Engine Marketing Professional Organization, SEM methods include: search engine optimization (or SEO), paid placement, contextual advertising, and paid inclusion.[1] Other sources, including the New York Times, define SEM as the practice of buying paid search listings.[2][3]
Google Adwords
Yahoo Search Marketing
Microsoft Live
Fuente: wikipedia
