Strategy Chronicles: SEO vs. SEM

What is Search Engine Marketing?

Search Engine Marketing (or SEM) is an advertising technique which uses paid advertisements that show up as results on search engines. These advertisements are often referred to as pay-per-click ads.

Ads may either be in the form of text-based ads or they may show up as images (known as product listing ads or PLAs) which may provide specific details about the product like price or rating. Personally, I consider SEM to be one of the most effective ways to promote a business, site or products over the internet.


SEM and SEO are two related but different terms. SEO, or Search Engine Optimisation, is the process of using specific keywords in order to rank web pages higher in a search engine. Sites essentially earn a free spot for having the most relevant content for a specific keyword. Whereas, with SEM a website is actually going out and buying advertisements from various search engines.

SEO is beneficial as it allows your site to gain visibility from those who may not have known about it before or were not necessarily looking for your site specifically. SEM, however, is better suited when targeting individuals who are already looking to buy a product or service.


In both SEO and SEM the use of keywords (or search terms) is critical. It is the use of these terms that make your site or ad show up on search engine result pages. The keywords you need to include on your page should be those most relevant to your page or product.

It’s important to realize that some keywords are more competitive than others. If you don’t have a massive advertising budget it’s worthwhile to focus on niche terms.

Keywords can also be negative, meaning that the word reduces the likelihood that your page will appear. If you’re selling bike tires you wouldn’t want to include ‘pump’ or ‘replace’ with your keywords as those looking for information on how to pump or replace a bike tire aren’t actually interested in buying a tire from you.

How Ad Auctions Work

An ad auction is how most SEM ads are sold. The advertiser, through the engine’s platform, specifies how much they’re willing to pay per click for a specific keyword. The engine combines this bid with an advertiser’s quality score (related to the relevance of your keywords and your click-through rate). Ultimately this will decide how well your ads are ranked on the search engine.

Bringing everything together, SEM is heaven for many businesses because it means customers are actually looking for you. In practice, it takes a bit of work and research to make SEM work for one’s individual business but it will most certainly be worth it on the long run.