SEM is a lot more than just installing keywords into an article.
It is the process by which a website gains traffic through its online visibility. The higher your visibility the more traffic you are likely to receive.
SEM is like a catchall phrase that includes everything you do to get your website noticed online. Two of the most important aspects of SEM marketing are gaining traffic from free advertising mediums. The other of course is paying for traffic. The number of web sites increased very rapidly in the world in the 90′s this is when search engines were developed to help browsers find what they were looking for. Of course each search engine has a business model that helps them to stay in business. They make money by doing this. If they didn’t they would not be around.