The Differences Between SEO and SEM

A common question in digital marketing is: SEO and SEM – What’s the difference between these two channels?

Before we dive into this subject, we should briefly touch on the issue of Google search engine results. To put it simply, Google search results are broken down into two main categories: paid search results and organic search results.

Organic search occurs when someone simply types a keyword or phrase into the Google search bar, which then generates the first page of several top-ranking websites. These websites are ranked highly based on certain SEO factors within the Google algorithm, which we’ll go into more detail below.

On the other hand, paid search involves Pay-Per-Click advertising (PPC), where ads are typically displayed at the very top of the Google results page.


SEO vs. SEM Overview

Search Engine Optimisation (SEO) is the process of continually improving the quality and quantity of traffic to a website (or specific webpage) so that it can rank in the organic, unpaid search engine results page (SERP).

You might be wondering how exactly websites are ranked on Google. Well, Google actually contains 200 Ranking Factors in their algorithm, including domain-related factors, page-level factors (such as title tags and meta descriptions), user interaction, backlinks and site-level factors. To put it simply, SEO can be divided into 4 main categories:

On-page SEO

This involves optimising your own website, which you can directly control and manipulate to get a higher ranking. You should aim to optimise your website around keywords that your target customer searches for in Google, Bing or any other search engine. The best on-page SEO practices involve including your keywords in your title tag, meta description and webpage URL, coupled with generating informative, easy-to-read content that is relevant to your audience.


Off-page SEO

It is important that your website appears credible and legitimate so that you can optimise your search ranking on Google. Off-page SEO refers to activities you must undertake outside of your website, meaning that you must acquire trust and authority signals from other websites. This includes writing a guest post on another blog or leaving a comment. It also primarily involves building high-quality backlinks to your website and social media engagement. Off-page signals such as E-A-T (expertise, authoritativeness and trustworthiness) provide a framework for this SEO.


Technical SEO

Refers to the optimisation of your website for the crawling and indexing phase. With technical SEO, you make it much easier for search engines like Google to access, crawl, interpret and index your website without any issues. Unlike on-page and off-page SEO, this doesn’t have anything to do with the actual content of your website or off-site promotion. Rather, you’re simply aiming to optimise your site architecture. This includes page loading speed, site navigation, internal links, category pages and improving overall user experience.


User Interaction

This level of user interaction or engagement indicates whether your web page is a relevant match for someone’s search. If your page has a high bounce rate, that could signal that your page isn’t providing someone with the correct answer to their query. When Google deems your webpage to be a bad fit for that person’s keyword, your ranking can slightly drop on the search engine results page, or even disappear from the first page entirely.


So, what’s the difference between SEO and SEM?

Well, the key difference lies in the fact that SEO (Search Engine Optimisation) is purely focused on optimising a website to drive traffic from organic search results. In comparison, SEM, otherwise known as Search Engine Marketing, aims to gain traffic and visibility from both organic and paid search results. In this way, SEO is actually just one aspect that falls underneath the umbrella definition of SEM.

In addition to SEO, Search Engine Marketing also involves PPC (Pay-Per-Click Advertising), which has its own features and best practices. PPC is an increasingly popular form of digital marketing, where advertisers pay a fee each time one of their ads is clicked. Rather than earning traffic organically, it’s a way of buying visitors to your website. Here’s an overview of Pay-Per-Click advertising below:



Paid search advertising is all about bidding. With PPC platforms such as Google Ads or Bing Ads, you have to bid on a specific keyword. When someone searches for that keyword or phrase, your ad shows up on the search results page. Usually, if you’re the highest bidder of that word, you’ll rank better and appear above the other competing ads. When someone clicks on your ad, you have to pay for that bidding amount – this is known as cost per click (CPC).


Quality Score

An extremely important metric found within Google Ads. The Quality Score basically measures whether your ad is relevant to the search query of your target audience, and indicates the level of user experience impacting their search. If your ad has a high Quality Score, you’ll even get a discount per click. Represented on a scale of 1-10, the Quality Score is calculated based on the expected click-through rate (CTR), landing page experience and your Google Ad account’s overall Quality Score.


Ad Copy

Writing powerful ad copy is one of the most effective ways of optimising your PPC marketing campaign. If you have fantastic ad copy that compels someone to click on your ad, then this will improve your click-through rate (CTR), which in turn, leads to a higher Quality Score. Factoring in that juicy discount on each click, you’ll be paying less for the same click! On the other hand, if your ad copy is weak, then your Quality Score will decline and your PPC will become increasingly expensive.

SEO vs. SEM – The Key Differences


SEO can take a considerable amount of time (3 months on average) before you start seeing any noticeable results in web traffic or Google ranking. This is especially true if you’ve just recently launched your new website and you haven’t built many backlinks yet.

However, if you apply best SEO practices, you can speed up this process to several months! On the other hand, PPC – the other branch of SEM – gives you pretty much instantaneous results, including higher traffic and conversion rates. However, the ROI can take slightly longer to achieve.



While SEO attracts people due to its ‘free website traffic’ and ‘organic search results’ benefits, it actually isn’t as cost-free as many would assume. It can take quite a lot of money, time and effort to reach the first ranking on Google – this includes building a domain authority, cultivating a solid web infrastructure, regularly pushing high-quality content, and undertaking off-site promotion.
However, once you do reach this position, you won’t have to spend a lot of money to maintain it! In contrast to this long-term and more risky investment, you’re paying up-front for PPC for some guaranteed result, making it cheaper in the short term. But once you stop paying, your traffic will drop.



While it is ideal to focus on both SEO and PPC as part of your wider SEM campaign, there can be certain situations where using one can be more appropriate:

SEO is great if you’re a startup or small business with a limited marketing budget yet have more time to spare. While you’re not seeing the ROI for months (or even years if you aren’t doing it efficiently), it still makes more sense than spending all your budget on fleeting PPC ads. It’s also ideal if you’re good at content writing and link-building.

PPC can be prioritised when you have a consistent ad budget, meaning that you can experiment with keyword targeting, ad copy, landing pages and bidding. With a Google Ads account, you’re also able to access useful data, metrics and analytics like Quality Score, ROI, and conversion rates. This can inform future decisions for your PPC ad campaigns.


Need Help With Boosting Traffic to Your Website?

OMDIGI Group provides amazing SEO consulting that is carefully tailored towards your business’s needs. We work together with your business to create strategies that involve keyword research, site analysis, technical SEO, link building, web development and more.

With our PPC services, your business can also enhance brand awareness and increase exposure to your target audience on popular search engines like Google and Bing. Our paid search advertising is designed to drive more traffic to your website and boost conversions. Don’t hesitate to contact us for more information!

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