SEM or Search Engine Marketing is a form of Internet Marketing that seeks to promote websites by increasing their visibility in the Search Engine results pages. SEM have methods that include: Search Engine Optimization or SEO, paid placement and paid inclusion.  

SEO on Improved Page Rank

Search engine optimization is just one part of the process of getting your site an improved search engine ranking. Its major benefits are making your site more accessible to search engines and increase the number of your pages indexed. With over a million of people using search engines everyday to look for a product or service, it is therefore vital for any business to establish a strong presence in top search engines. The process of optimization is not that difficult because it is just a matter of understanding what search engines look for when they visit your site.