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SEO, SEA, SEM : What are the differences ?

SEO, SEA, SEM, you’ve heard of these terms before, perhaps even without knowing what defines and differentiates them.

The common goal of SEO, SEA and SEM is to rank a website as high as possible in the page results of a search engine like Google according to the search queries (keywords). There are many acronyms and definitions on the Web. Here is a simple guide that explains these terms.

Explicit definitions of the terms SEO, SEA and SEM:

Before discussing the differences between these acronyms, lets provide a short, but nonetheless accurate, definition of these terms.

Definition of SEO

SEO, which stands for Search Engine Optimisation, is a series of processes aiming to optimise a website. The aim of this optimisation is to secure the best possible visibility in the search engines’ organic results.

These processes can be divided into 3 categories:

  • The technical aspect, meaning everything that affects the website’s structure. The scope of this topic is broad! Technological choices may directly influence the website’s performance. The sooner this aspect is taken into account, the better.
  • The content aspect, which involves offering relevant texts (semantic richness, matching the search intent).
  • The off-page aspect, meaning outside the website. It brings together all the links coming from popular and authoritative external websites. This is known as backlinks.

Definition of SEA

SEA stands for Search Engine Advertising. This term refers to commercial or advertising actions that increase the visibility of a website on search engines.

SEA makes it possible to be visible via text ads on Google search results, on websites via Google Ads. Visual ads (display) are also available.

To promote visibility in the ads displayed on search engines, SEA works on a bidding system. The cost of the ad depends on the level of competition, search volume per query, etc. The success of the campaigns thus depends on the budget assigned, but also on the quality of the ads according to the content provided (Quality Score).

SEA is often referred to as « paid search ». Although these sponsored links do influence the visibility and therefore the traffic of a website, this discipline is more of an advertising activity.

Definition of SEM

Search Engine Marketing, shortened to SEM, refers to all activities aimed at boosting the visibility of a website and generating traffic. This involves methods related to search engines, such as SEO and SEA, but also practices related to social media, such as SMO.


SEO is often contrasted with SEA because these are the two most common practices in search engine referencing.

Here are some examples showing the differences between SEO and SEA:

  • SEO is mandatory for any website with a visibility objective. It is necessary to optimise your website via organic referencing if you want to be displayed in the SERPs.
  • SEA allows you to see the results of your campaigns straight away. On the SEO side, you need to be patient in order for the search engine indexes to be updated. Let’s not forget the competitors’ actions which also impact the results!
  • The sustainability of results is in favour of SEO, as the gain in visibility and traffic is felt over the long term. The SEO strategy can also be adjusted over time to adapt. SEA plays a much more ephemeral role in this race for visibility. Indeed, the loss of results will be effective from the second the advertising campaign stops.

SEO and SEA are two very different jobs. They both have strengths and weaknesses. It all depends on how the techniques are developed and the investment made. Different does not mean incompatible. When combining these two acquisition channels, you are able to optimise the cost of your campaigns.

SEO and SEA are therefore complementary, and when they are combined, we speak of SEM.

Any other acronyms to be clarified?

By now you know the ins and outs of SEO and SEA, SMO and even SEM. So why not carry on with our analysis by talking about SXO?

What is the role of UX?

SXO is often described as the addition of SEO (Search Engine Optimisation) and UX (User Experience). In simple terms, UX represents the overall experience of a user over the whole period of interaction with a website.

The direct importance that Google gives to UX metrics is subject to some debate. This is the area of Core Web Vitals. Therefore, SXO is a process in which the user lands on a website through a well-designed SEO strategy that generates traffic, then UX comes into play by converting that traffic with a user-friendly browsing experience.

Translated by Nicolas Piquero.
Nicolas Piquero is a seasoned SEO with 6 years experience. He worked as an in-house, agency and freelance SEO, with various major european companies. Being both a and power user, it was obvious that he could be an ambassador for babbar’s tools. So, being based in London, he is the first babbar ambassador for the UK.