Search Marketing (Search Engine Marketing, SEM) - a set of marketing methods to improve the visibility of the site in search engines (search results, SERP, Search Engine Results Pages).
Three main methods of search engine marketing:
Search engine optimization (Search Engine Optimization, SEO) - a set of measures aimed at improving the ranking of a site for a key request in the search results, by changing the structure and content site (internal optimization), as well as the installation of external links to your site from other sources (external optimization).
Contextual search advertising (Pay Per Click, PPC - pay per click) - advertising a site located in a block of text. Cost-per-click on the key demand and position the site in a text (ad) block depend on the level of competition in an auction this key demand, but also on other factors.
Paid inclusion (Paid Inclusion) - provides a guaranteed inclusion of the site's search engine or directory.