The terms SEO and SEM are often used interchangeably, despite there existing a key distinction between the two acronyms. Articles discussing search engine optimisation might use “SEO & SEM” throughout, with no further elaboration — but what is the difference?

Man holding a tablet with Online Marketing checklist

Like most SEO acronyms and initialisms, it’s not as complicated as it seems.

SEO stands for Search Engine Optimisation, and refers to anything done in an effort to increase a website’s ranking in search engine result pages (SERPs).

SEM stands for Search Engine Marketing, and refers to paid listings in search results — advertisements, essentially.

Despite SEM technically being SEO, people tend to describe SEO as organic efforts to increase a site’s visibility in search engines’ results, whereas SEM is paying for that visibility by means of purchasing advertising slots, so when you search Google for “footie shirts”, your website appears top of the pile! (Assuming the user isn’t utilising an ad-blocker…).

What is SEO?

Put simply: SEO is the process of increasing a website’s visibility in search engines’ results. Broadly, SEO refers to the practices and methods used to achieve this increased visibility.

Good SEO is important — if your website ranks poorly in search results, you’ll have fewer visitors, and your exposure is diminished. If you utilise good SEO practices, you’ll naturally rank higher in search results, and more people will find your website. 

To highlight how important it is to rank highly in search results, consider the findings of extensive research conducted by online advertising firm Chitika, published in their 2013 report The Value of Google Result Positioning (PDF):

  • Less than 10% of people visit Page 2 of Google’s results
  • The first result in Google receives 33% of clicks
  • Page 3 is visited by a mere 1.1% of people; page 4 by 0.4%, and page 5 by 0.2%

On-page vs Off-page SEO

SEO is generally broken down into two distinct “types” — on-page SEO and off-page SEO, also known as on-site and off-site.

On-page SEO

As the name implies, on-page SEO refers to actions you take on your site to improve your ranking in search results.

The majority of SEO takes place on-page, and includes optimisations such as using SEO-friendly URLs, including your title in an <h1> tag and subheadings in <h2> tags, using your keywords early on and throughout the page, ensuring image elements have an appropriate and SEO-friendly alt attribute, creating descriptive meta descriptions for your pages, and so on.

Off-page SEO

Once again, off-page SEO refers to actions you take off your site to positively impact your ranking in search engines’ results.

The best example of off-page SEO is building backlinks — links on other websites that point to yours. These might be natural backlinks, where users have linked to pages on your website of their own volition, or manual backlinks. Manual backlinks are those you have either posted yourself (e.g. sharing a link to your site on your social media platform, on somebody else’s forum, and so on) or they may be links you have requested others post, for instance you might request customers provide a link to your website on their own website.

What is SEM?

SEM stands for Search Engine Marketing. When people talk about SEM, they’re referring to placing paid listings in search results — i.e. advertisements, such as those you might see at the top of Google’s result pages.

Again, while SEM can technically be said to fall under the ‘SEO’ umbrella, SEO and SEM are considered to be separate topics.

Here are a few SEM activities:

Conducting an advertising campaign

Carefully selecting the intended audience you intend to market your website to and establishing an advertising campaign.

Performing your research

What keywords should you target? Who is your intended audience? 

Advert copywriting

Writing a engaging, attention-grabbing piece of text for your advertisement to hook people in.

Using analytics to assess performance

Using appropriate tools to monitor crucial metrics like clickthrough rate (CTR), cost-per-click (CPC), number of impressions, and so on. Most advertising platforms provide these analytics for you, and you may additionally use a tool such as Google Analytics to further track your advertising campaign’s success.

Considering (and reconsidering) your budget

Staying within a sensible budget which fits your available resources and meets your needs appropriately.

Assess your goals

What do you hope to achieve through your SEM efforts? How many new visitors do you hope to draw in? Do you have a conversion rate in mind; what percent of your new visitors do you expect will purchase your product or service, for instance?

Further reading

Wikipedia – Search engine marketing

Wikipedia  Search engine optimization

Wikipedia  Search neutrality

Google Search Console Help  Do you need an SEO? – What is the Difference Between SEO and SEM?