Author | Zach Wales
Bio | Zach Wales is a senior strategist in search marketing who has been honing complimentary SEO & SEM strategies for over a decade. He architected the digital marketing department of a full-service agency, HZDG, where his clients included NVR, Inc.; Hilton Hotels; Organic Valley, and more.
Search engine optimization (SEO) and search engine marketing (SEM) have complemented one another as marketing channels since the dawn of Google AdWords (Google Ads’ pre-2018 name) in October 2000.
As their names suggest, SEO and SEM are two sides of the same coin. Troves of blog posts, podcasts, and other media have attempted to explain how this is so. Indeed, the SEO/SEM discussion has evolved over the years in stride with search engines themselves, which have evolved to deliver more user-tailored experiences.
This article will address some of the present-day differences between SEO and SEM, and show you how you can leverage them in your all-encompassing search strategy.
We stand at an important crossroads in the SEO/SEM relationship narrative. In recent years, Google, the all-powerful influencer of search marketing trends, has gotten better at detecting keyword semantics and their respective contexts.
The implications on SEO and SEM are profound. The winners in this new era are marketers with a full-funnel perspective on search, and a willingness to share insights between SEO and SEM.
Special note: For simplicity, this article will refer to the practitioners of SEO/SEM as “an SEO/SEM” (singular) or “SEOs/SEMs” (plural). The gender-neutral pronouns “they/their” will be used in place of the gender-specific singulars “he/she.”
What's the difference between SEO & SEM?
As marketing channels, SEO and SEM share the same “What”: Their basic objective is to promote website content in search engines. They also share the core strategy of targeting the intent behind people’s search terms or keywords.
The main difference between SEO and SEM resides in the “How” and “Where.” Both channels value keywords for their respective search volumes and the likelihood of conversion. But each utilizes keywords in slightly different ways.
For the purposes of this article, we will define SEO and SEM as follows:
SEO is the ongoing creation, enhancement, promotion, and technical maintenance of website content that appears in the organic (or non-paid) real estate of search engine results pages (SERPs).
More than a channel, SEO is an earned marketing effort. Keyword rankings are earned through on-page (e.g. website content optimization) and off-page (e.g., content marketing) efforts.
SEO leverages keywords like a builder leverages cement. They are building blocks in planning, creating, and optimizing website pages that appear on desirable SERP property for those keywords.
SEO is a long game. Organic keyword rankings can take months—and no small amount of effort—to come to fruition. Once a top ranking is earned, the effort doesn’t necessarily decrease. That depends on how desirable one’s keywords are, and what one’s competitors are doing to earn their place in the SERPs.
SEM is the strategic placement of ads within a search engine’s advertising real estate. It happens to go by other names like “PPC” (pay-per-click) or “AdWords,” just as it comes naturally to say “Kleenex” for any brand of facial tissue.
SEM is a paid marketing channel, but like SEO, on-page optimizations (e.g., landing page UX) come into play.
In SEM, keywords are bid upon in real-time online auctions for the time, intent, and actions of potential website visitors. Generally speaking, ads appear in desirable locations when you outbid your competitors in that micro-moment, AND when the webpages your ads target meet the search engine’s (really Google’s) criteria for quality and keyword relevance (known in Google Ads as Quality Score, the counterpart to Core Vitals in SEO).
Compared to SEO, SEM is a short game. Brands with deep pockets may run Google Ads continuously throughout the year, but SEM tactics have near-term results. As with SEO, keywords serve as building materials for strong and relevant landing pages. But like all things PPC, they can be surgically applied (or bid upon) and switched off on demand.
The “How” and the “Where” of SEO and SEM are ever-evolving. The present-day visual landscape of Google SERPs—complete with image carousels, knowledge cards and more—is a far cry from the ten, all-text results of the pre-2007 era.
Understanding that landscape provides insight on how to situate SEO and SEM in your broader marketing strategy.
The Role of Google in SEO & SEM
Google has always dominated the global market of online search and its intent. It has also maintained a technical edge in that space. It has the most sophisticated algorithm and has always been a contributor to, if not the source of, new SEO/SEM trends. Most updates you hear about in non-Google search engines are their attempts to catch up with Google’s innovations.
Today Google accounts for 76 percent of all online searches, which amounts to over 3.5 billion daily searches (or 40,000 per second), and 1.2 trillion each year. Baidu takes a distant second 15 percent, while Microsoft Bing, Yahoo, Yandex, Ask, DuckDuckGo, Naver, AOL, and Dogpile make up the remaining 9%.
As stated earlier, there have been numerous changes to Google’s SERP-scape since 2007 (the year after Google acquired the world’s leading video search engine, YouTube). Behind these changes is the commonly held objective of all search engines: To generate revenue by making their product as relevant and reliable as possible.
What does this mean to SEO and SEM? Fairness, in a word. Google has made it increasingly impossible to merely buy your way to the top, or to clutter SERP real estate with flimsy, overly exaggerated, or misleading information.
Sure, bid amounts matter in SEM, as with any auction. And bidding strategy is a key pillar to managing Google Ads. But their success hinges on Quality Score, Google Ads’ unique criteria that weights webpage quality and user experience as much as—sometimes more than—how you flex your bids.
Conversely, link building matters in SEO. How else can Google measure the authority of one website without seeing how other credible websites (e.g., ones with a top-level domain of .gov or .edu) link to it?
But Google has gone to great lengths to identify and penalize SEOs who create superficial microsites for the sole purpose of link building. By doing this, Google is policing junk results from its product: relevant results.
The following rule of thumb helps illustrate the prominence of Google in SEO: If you ever doubt the career credentials of a new SEO vendor or staff candidate, just ask them to talk about Panda and Penguin. If they can speak to how these Google updates have helped level the SEO playing field over the past decade, they’re knowledgeable.
If they do the same thing but with a visceral expression of agony, they are experienced.
Is SEO or SEM Better?
This is a trick question. No one answer applies universally. As a paid advertising channel, SEM campaigns can return results within days of being launched. SEO typically takes months, or weeks depending on the strength of your domain.
For that reason alone, one might favor SEM during times of urgency—when your CEO demands a 5 percent increase in sales between November and year’s end.
But the case for SEM cannot be made on timelines alone. If your business lives in a saturated market dominated by large brands who are heavily invested in Google Ads, then SEM could be a money pit (unless you aim for very niche longtail keywords, which might convert well but not with the desired volume).
Conversely, if you’re selling to a relatively exclusive audience with a new or unique offering, SEM could be your next marketing windfall.
Timelines are one of many variables that weigh in on the SEO vs. SEM debate. The only constant in that debate is that everyone prefers the best of both worlds. Anyone with a sales funnel has a need to familiarize people with their products/services and then convert them. The best results occur when both options are available in the SERPs.
Speaking to this, Brainlabs SEO Strategist Anthony DeSordi says: “Our tools and processes for keyword research are very good at identifying top and middle-of-funnel keyword opportunities. The data from PPC helps us with the higher-converting, lower-funnel keywords.”
Joaquín Espliguero, who works with DeSordi as a Paid Search Strategist, adds, “We can then utilize the upper-funnel keywords from SEO to generate awareness campaigns. These insights also bleed into non-search paid tactics like social media campaigns. If done right, you can teach your audience which keywords to use to arrive at the products/services that you want to sell.”
BERT and the Relationship Between SEO and SEM
The updates to Google’s search algorithm and its Ads platform are numerous. Standalone resources like Moz’s Google Algorithm Update History and Screaming Frog’s Google Ads History provide comprehensive timelines detailing how these updates impact the SEO/SEM industry.
Each of those updates reflects a sign of the times in SEO and SEM—together and separately. Knowledge of this relationship is the first step to capitalizing on it.
The Google BERT Update
BERT, short for the easy-to-remember Bidirectional Encoder Representations from Transformers, is a Google algorithm update that launched in October 2019. BERT improves the way Google understands the context and intent of search queries.
Because BERT has implications on the way Google “perceives” keywords, it’s worth noting how it impacts SEO and SEM. And what you can do about it.
Google BERT & SEO
The BERT update essentially advanced Google from understanding the meaning to understanding meaning within meaning. It improved how Google distinguishes between phrases from sentences, and how to interpret “polysomic nuances”—words with two or more meanings.
The BERT update dovetails with the similarly-purposed Panda (2011), Hummingbird (2013), and BrainRank (2015) updates. Each represents a milestone in Google’s ability to detect quality content and keyword semantics.
For marketers already heeding the SEO best practice of creating long-form, credible content, BERT was like an act in good faith: It was (more) proof that Google was capable of rewarding their efforts.
What that looks like in SEO is increased visits from long-tail keywords, and therefore greater potential for webpage content to rank for voice search queries, Featured Snippets, Knowledge Cards/Panels, Image Packs (for optimized image & media files), and the like.
Google BERT & SEM
Although the direct implications of BERT are felt more in SEO than SEM, the update ushered game-changing trends in Google Ads.
Google said it is now using BERT in Google Ads as part of its "improved understanding of search intent and more predictability in how keywords match." This improved understanding resulted in the death of Google Ads’ Broad Match Modifiers. Google’s machine learning can now find the context and intent of broad match keywords without modifiers.
Moreover, Google’s emphasis on Responsive Search Ads, along with its sunsetting of Expanded Text Ads, points to a new era of confidence in automation and artificial intelligence.
RSAs let you enter 15 headlines and four descriptions for each ad. Google chooses the most relevant combination of headlines and descriptions by analyzing various cues from the user—but also from your webpage content.
“The more headlines and descriptions you enter, the more opportunities Google Ads has to serve ads that more closely match your potential customers’ search queries,” says Google, adding that this “can improve your ad performance.”
Indeed, if your SEM campaigns do not include RSAs across the board, you’re missing a very important bus. But how does this relate to BERT?
BERT, SEM and SEO Working Together
If the AI that empowers Google Ads to choose the “best of” 15 headlines and four descriptions sounds like the AI that empowers Google to transpose webpage copy into a Featured Snippet in organic results, then you might know where this is going.
What makes two of 15 headlines better than the rest? Relevance.
What makes them relevant? Let’s say, hypothetically, that the most compelling and converting headline in your RSA arsenal is “Buy Weatherproof Shoes.” If there is no corresponding landing page copy that elaborates on the benefits of weatherproof shoes, this winning headline won’t see the light of day. It becomes a conversion gap in your SEM strategy.
This might seem like an obvious and avoidable oversight, but not if your approach to SEM is siloed from SEO. After all, a well-formulated SEO plan would have uncovered the importance of “weatherproofing” in keyword research and avoided such apparent content gaps.
But let’s say you don’t have that luxury: Your SEM campaigns were launched without giving SEO a thought. You work for the most siloed marketing department in your industry.
The above factors may stack the cards against you. But if you understand the “how” behind Google’s AI, you are better positioned to anticipate things like semantic associations and content gaps. And that something can be done about them.