First of all, SEM does not compete with SEO. It targets different objectives. When you spend money on search engine marketing, your content will rank for as long as the campaign continues. The page goes back to its initial state as soon as you run out of money. SEO, on the other hand, takes time to appear on search results. For as long as there is a demand for the product or service and your page holds the top ranking, it brings more traffic on a daily basis. Thus, you continue earning for a long time. SEM is best suited for seasonal products and quick marketing results. But SEO accomplish your broad and long term objectives.