SEO is a long time process and search engine marketing give you instant result ....But Search engine marketing is much costly or less effective as SEO gives long time result but need to smart work
SEO - process of improving the visibility of a web site in search engine results. SEM - is the process of gaining traffic from or visibility on search engines.
SEO refers to Search Engine Optimization whereas SEM refers to Search Engine Marketing. - In a more broader sense, SEO is a technique of optimizing the website with the keywords related to the content and generating the traffic from targeted keywords, while, - SEM is an Internet Marketing process that helps in promoting the visibility of a website in Search Engine Result Pages. This includes Pay per Click advertising, Paid Inclusion, Search Analytics etc. SEO part of a website should be done before SEM to begin.