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, and paid inclusion.[1] Other sources, including the New York Times, define SEM as the practice of buying paid search listings.
Market structure
North American advertisers spent US$9.4 billion on search engine marketing, a 62% increase over the prior year and a 750% increase over the 2002 year. The largest SEM vendors are Google AdWords, Yahoo! Search Marketing and Microsoft adCenter.[1] As of 2006, SEM was growing much faster than traditional advertising and even other channels of online marketing