For those of you just started marketing in search engines, the term SEM and SEO have probably popped up. Search engine marketing (SEM) is the listing of your sites on search engines, while SEO (search engine optimization) is the practice of optimizing your websites' rank in the search results. SEO gives you a better ranking (which websites appear first during an entry are determined by ranking-the highest ranking first). SEO increases the visibility and accessibility of your site by giving you the best search position (ranking) possible. SEO is one of the ways SEM is accomplished. SEO is the methods used to achieve rankings in the "organic" or unpaid rankings SEM is a type of internet marketing. It is the attempt to promote websites on the engines. Different ways of achieving SEM is through paid placement, SEO, paid inclusion, contextual advertising, or PPC advertising. SEM is done through engines such as Google (the largest), Yahoo, Bing, Ask and many others. You will see the terms SEO and SEM alot on the web. These subjects are discussed at great lengths on the internet and rightly so. SEM and SEO are key to online business success. The engines have defined how users obtain information on the internet. Without SEM and SEO your website and web business would not be tapping into the power of user searches. The internet will continue to grow and prosper over the coming decades and the engines will continue to dominate the flow of information across it. And those businesses that excel in SEM and SEO will be well placed to profit from it.