SEO and SEM

Search engine marketing (SEM) is a form of internet marketing that involves the promotion of websites by increasing their visibility in search engine results pages (SERPs) through optimization (both on-page and off-page) as well as through advertising (paid placements, contextual advertising, and paid inclusions). Depending on the context, SEM can be an umbrella term for various means of marketing a website including search engine optimization (SEO), which adjusts or rewrites website content to achieve a higher ranking in search engine results pages, or it may contrast with pay per click (PPC), focusing on only paid components.