While some people use SEO and SEM interchangeably, SEO (search engine optimization) is actually a part of SEM (search engine marketing).
SEO refers to the process of using on and off page factors (typically free) to get your web pages ranked for your chosen keywords in order to get more search engine traffic to your sites. SEM takes it a step farther to include using paid search engine listings and paid inclusion to get more traffic to your websites.
SEM is a broader term than SEO. Where SEO aims to provide better organic search results, SEM uses the search engines to advertise your website or business to Internet customers and send a more targeted traffic to your Web site.
The difference between SEO and SEM is simply that Search Engine Optimization is part of Search engine marketing or Search marketing as it is widely known. Both processes aim in increasing visibility in search engines. SEO is about optimizing the web property to get better rankings in the search results while SEM goes beyond SEO. It involves other methods as well which can get you more search engine visitors like PPC advertising.
No confusion SEO is used to optimize the search engine to increase the traffic to your website through On-page and Off-page optimization. Whereas SEM is used only to advertise your website in the internet through various techniques the only purpose of SEM is increasing the traffic through marketing in the internet.
Actually, there are many definition between SEM and SEO including also their uses and how does it affect to the people. But, in my stand this two types of engine are probably know and it is useful in different ways.
SEO is Search Engine Optimization in which we optimize our website for search engines.
SEM is Search Engine Marketing in which we promote our through many marketing tactics.
SEO refers to Search Engine Optimization. Which affects Google organic listing. While SEM refers to Search Engine Marketing. Its totally related to Paid listing on search engines.
SEO stands for search engine optimization while SEM stands for search engine marketing. SEM is a broader term than SEO. Where SEO aims to provide better organic search results, SEM uses the search engines to advertise your website or business to Internet customers and send a more targeted traffic to your Web site.