Paid search marketing is the process of gaining traffic by purchasing ads on search engines. It is sometimes referred to as CPC (cost-per-click) or PPC (pay-per-click) marketing, because most search ads are sold on a CPC / PPC basis.
Some people also refer to paid search as SEM, through here at Search Engine Land, we consider SEM (search engine marketing) to be an umbrella term that encompasses both paid search and SEO (search engine optimization).
