SEM vs. SEO: What’s the difference?

SEM vs. SEO: What’s the difference?

Alex Sleeper

The search engine is an invaluable tool for marketing. Search engines are major traffic hubs, like a busy international airport, they direct users to their virtual destination; in fact, 93% of all web traffic is mediated by search engines. This is why search engine marketing, or SEM, is universally used to drive immediate results.  

Whether you’re looking to increase web traffic, promote brand awareness, or generate new leads – SEM works. 

For marketing newbies, the term can be confusing; it’s easy to confound search engine marketing with other types of search engine-related marketing, like SEO. But we’re here to clear it up.

Keep reading to learn more about SEM and why it’s a great tool to drive ROI.

What Is SEM?

Google any question or phrase and you’ll notice that at the top of the results page, there are sponsored results marked with the word “ad.” This is the mark of SEM, an acronym for search engine marketing, or paid search advertising.

Generally called “search campaigns,” search engines allow businesses to bid for ad placement on the search engine results page for specific keywords. The higher the bid, the better your chances of seeing your ad at the top of the page. However, search engines rank ads not only on their bid amount, but also on the ad’s quality: relevancy to keyword, expected click-through-rate (CTR), and landing page optimization.

For example, a Phoenix-based sports bar should bid for ad placement on queries such as: sports bar Phoenix, AZ, sports bar PHX, sports bar near me, where to watch sports in Phoenix. The more engaging the ad, and the better optimized the destination link, the higher the ad will be placed, improving the likelihood it will be clicked on.

Furthermore, search engines only charge advertisers when users click on their ads; this payment model is called pay-per-click or PPC. Other ad types may employ different methods, such as cost-per-mile (CPM), which charges advertisers every 1000 views.



Search engine marketing (SEM) and search engine optimization (SEO) have similar names and similar goals, but operationally are quite different. Here’s what we mean:


One of the most salient differences between SEO and SEM is the results timeline. SEO is a long-term tactic that aims to increase organic traffic to your website by improving your website’s rank through optimization activities. Optimization includes posting blog content, embedding your main keyword across pages (on page SEO), and technical tasks such as re-indexing your website and redirecting broken links.

SEM, on the other hand, is paid advertising that drives results immediately — you pay for these visitors, they aren’t organic.

Additionally, SEO and SEM results look different on search engine results pages (SERPs). SEM results are visible at the very top of the page and denoted with the word “ad.” SEO results are organic and are served below these ads; they are webpages that the Google algorithm selects as being highly relevant to the query and a trustworthy domain.

Finally, SEM is easier to test, and the effects are visible through short-term data. You can optimize ads for effectiveness day-by-day, and campaign-by-campaign, by tweaking the copy, imagery, bid, audience, and more. Meanwhile, SEO is a cumulative process; it’s effective, too, but it will take you longer to see results.


In many respects, SEO and SEM have similar goals. Both are intended to improve website visibility on SERPs and to drive website traffic from relevant searches to your products and services by using keywords to make connections.

Both tactics generate analytics that can be used to get a deeper understanding of your target audience, or to uncover new audiences. And SEO and SEM will both need refining over time as you test and tweak to improve outcomes.

When You Should Choose SEM

This isn’t a one-or-the-other situation. SEM and SEO should both be integral parts of a healthy marketing strategy: 68% of all traceable website traffic comes from organic and paid searches (the remaining from direct and referral). But in certain cases, one method will be better than the other. Here are a few circumstances when you should invest in SEM.

You’re A New Business

SEM is great for a new business that needs to quickly drive brand awareness and leads. SEM works more quickly than SEO — it can take a long time (often several months) to craft SEO content that will get results. But once you push an SEM campaign live, your ads will immediately show up and can start getting views and clicks.

You Need Leads

New business or not, SEM can help any organization that’s short on leads and is looking to close new business ASAP. SEM can not only help with leads, but can boost your conversions, too; identify queries that signal when your target audience is ready to convert and build ads for those keywords.

Your Visibility Is Low

Maybe you already have an SEO strategy, but you have low visibility on SERPs with organic results. Adding SEM into your marketing mix can help. By strategically choosing the right keywords and keyword phrases, you can up your visibility and brand awareness as people search for those industry terms and come across your ads.

You Have A Small Budget

SEM doesn’t have a minimum investment – you can spend a small amount and still get decent ad saturation, especially if the ad is engaging. When it comes to ROI, the cost-per-click (CPC) with SEM ads is almost always worth it. Low CPC with high conversions makes SEM feasible even with a small budget.

However, if the CPC is high and the margins are low, it might not be worth it. There are techniques you can use to lower your CPC, like adjusting your bidding tactic, narrowing audience targeting parameters, or selecting keywords with less competition.

You Need Data

SEM can be used to collect data on your target audience, helping you see which keywords or topics resonate most with them. This allows you to segment campaigns to target ads to specific groups of consumers based on what they find engaging. Plus, your SEM analytics can inform your SEO strategy, too.

Take Your SEM Strategy to the Next Level

When it comes to marketing — whether SEM or beyond — Extu has your back. We make marketing painless through fully automated monthly email campaigns, plus personal support from our highly trained team. That means you’ll have more time to focus on what matters while we devote our time to warming up leads. Interested?