Search engine optimization (SEO) is the process of improving the volume and quality of traffic to a web site from search engines via "natural" ( "organic" or "algorithmic" ) search results. Usually, the earlier a site is presented in the search results, or the higher it "ranks", the more searchers will visit that site. SEO can also target different kinds of search, including image search, local search, and industry-specific vertical search engines.
Some search engines have also reached out to the SEO industry, and are frequent sponsors and guests at SEO conferences and seminars. In fact, with the advent of paid inclusion, some search engines now have a vested interest in the health of the optimization community. Major search engines provide information and guidelines to help with site optimization. Google has a Sitemaps program to help webmasters learn if Google is having any problems indexing their website and also provides data on Google traffic to the website. Yahoo! Site Explorer provides a way for webmasters to submit URLs, determine how many pages are in the Yahoo! index and view link information.
Guerrilla marketing is an unconventional way of performing promotional activities on a very low budget. Such promotions are sometimes designed so that the target audience is left unaware they have been marketed to and may therefore be a form of undercover marketing (also called stealth marketing). The ethics of guerrilla marketing have often been called into question due to an alleged deceptive, misleading, or subtle nature of the campaigns.