Introduction to Search Engine Marketing and Online Advertising
A search engine helps users find the things they're looking for online. The user types a word or phrase, called a query, into the search engine, which then displays a set of results that are relevant to the query. Most search engines provide two types of results listings in response to the same user query: organic (also called "natural" or "free") listings, and paid listings (i.e., advertisements).
Most search engines rank the results within each type of listing -- in other words, they determine in what order to show the listings on the results page -- according to how relevant the result is to the user's query, with the most relevant appearing at the top of the page. Each search engine calculates relevancy in a different way for each type of result (organic and paid). This is one of the main differences between one search engine and another, and it's a factor in many users' decisions about which search engine to use.
How The Google Search Engine Works
Although both organic and paid results appear in response to the same user query, the results are independent of each other. The ranking of an organic search result has no bearing on the ranking of any ads, and vice versa. This makes it possible for an advertiser to perform well in the paid listings and have an ample online presence, even if their site isn't present in the top organic search results.
In the Search Engine organic results, relevancy to the user's query is determined by many factors for Google Right now over 200 factors.
Paid Search also uses a combination of factors to rank paid listings, which is another topic. Each type of listing -- organic and paid -- has a type of marketing approach associated with it
Search Engine Optimization
Search engine optimization (SEO) involves building new websites, or changing existing websites, so that they rank highly in a search engine's organic listings when users search on terms that are related to the site's content.
Search Engine Marketing
Search engine marketing (SEM) is the process of promoting and marketing a website through paid listings (advertisements) on search engines. Our Focus here is on SEO.