The difference between SEO and SEM is simply that Search Engine Optimization is part of Search engine marketing or Search marketing as it is widely known. Both processes aim in increasing visibility in search engines.
SEO is about optimizing your website to get better rankings in the search results while SEM goes beyond SEO. It involves other methods that can get you more search engine visitors like PPC advertising.
Search Engine Optimization (SEO)
For the purpose of doing a comparison between SEO and SEM, it is important to start with the definition of SEO so that it is clear for everyone what the difference between the two is.
What is SEO?
SEO is the process of optimizing your web site for the purpose of getting free traffic from search engines.
An optimized web site is more easily understood by Search engine crawlers and this increases the chances of ranking higher in SERPS.
On-Site and Off-site SEO
There are 2 main pillars of SEO, what is called on-site SEO and off-site SEO. On-Site SEO are rules you can apply on your website or blog so that it’s search engine friendly.
For example, you need to use optimized titles, good descriptions, well formatted URLs, correct use of H1, H2 and images and many more.
You can read our SEO Tutorial for beginners, get a good idea of how you can optimize your web site for search engines.
Off-site SEO refers to the process of getting votes from other web sites for the purpose of increasing your web site’s trust in the eyes of search engines.
For beginners this may be confusing but try to think about it like a ranking system where the web site who has the most votes ranks higher.
Votes in our case are links coming from other web sites to your site. That is also the reason why off-site SEO is referred to as link building.
To avoid any misunderstandings, it’s not only a matter of how many links you have pointing to your website but also from where these links are coming (and a number of other factors).
Search Engine Marketing (SEM)
Search Engine Marketing is over and above SEO but it’s only a subset of your overall Internet Marketing Strategy. The diagram below shows the relationship between Internet Marketing, SEM and SEO.
As you can see there are many more ways to increase your web site’s traffic besides SEM and SEO.
What is SEM?
So, SEM is the marketing process with a goal of getting more visibility in search engines either by getting more free traffic (SEO) or paid traffic (Paid search advertising).
Through paid search advertising you essentially buy advertising space in the search engine results. So instead of trying to rank higher and get free traffic you pay to appear in front of the searches.
The most well-known advertising agency for PSA is Google Adwords. Through Google adwords you can get your ads to appear in the Google search results and you pay only for the clicks on your ads.
This is also the reason why the whole process is called Pay-per-click or PPC. Bing and Yahoo have a similar system but it not so successful and widely known as Adwords.
Importance of SEM Traffic
SEM traffic is considered the most important source of Internet traffic because it is targeted. It is widely accepted that people use search engines to find a solution to a problem, an answer to their question or to learn how to do something.
So when searches click on a web site from the search results or click on an ad, they are more likely to convert. The relevancy of the displayed web sites and ads makes SEM traffic more valuable than any of the other sources.
Facebook and twitter are trying to optimize their advertising platforms to utilize targeted traffic but still traffic coming directly from search engines has a better ROI.