Could you anyone tell me what is the main difference between SEO and SEM?

+9  A: 

SEO - Search Engine Optimistaion

Search engine optimization (SEO also search optimization) is the process of editing and organizing the content on a webpage or across a website to increase its potential relevance to specific keywords on specific search engines and importantly ensuring that external links to the site are correctly titled and in abundance.

SEM - Search Engine Marketing

Search engine marketing, or SEM, is a form of Internet marketing that seeks to promote websites by increasing their visibility in search engine result pages (SERPs).

Some of the methods used for SEM are:

  • Paid Inclusion

  • Traditional Ads

  • Pay-Per-Click (PPC) Advertising

There's a good summary here of the main differences between them


SEO is a small part of SEM, it is very important though.

Regarding to SEO, it requires you to make some adjustments to you web sites so that they are search engine friendly! Which means your web site will rank high in reach result on some key words.

SEM includes PPC, like google AD. you need pay for it, however the intentions are the same:make you websites visible to the right viewers!


SEO comes under SEM. SEO is one part of SEM which is used for putting web site in top searching results in all search engines.