SEO earns you organic visibility in search results, one of the most durable competitive advantages in digital marketing. But only if you understand why it works and how to build it.
The brands that appear at the top of search results consistently earn more trust than those that don’t.
In this guide, we explain what SEO is, how it works, and 11 concrete reasons why SEO is still important in a search landscape that now includes AI Overviews, AI Mode, and ChatGPT.
What is SEO?
Search engine optimization (SEO) is the process of optimizing a business’s website content, structure, and overall online presence to improve its organic (unpaid) visibility in search engine results pages (SERPs).
In other words, SEO can help you earn visibility across Google, including in AI Overviews, AI Mode, and organic rankings. Like this:
SEO is one of the two main pillars in search engine marketing. The other is pay-per-click marketing (PPC). This is when you pay to appear as a sponsored search result.
How does SEO work?
SEO works by helping search engines understand what your content is about so they can rank you for appropriate queries.
Google wants to rank webpages that:
- Satisfy search intent (what the searcher is looking to achieve)
- Demonstrate experience, expertise, authoritativeness, and trustworthiness (E-E-A-T)
- Load quickly and perform well
- Are easy for search engines and users to navigate
These signals (among others) also help AI systems decide which results to surface. So working on your site’s SEO can also help you build visibility in AI-generated answers.
Some of the most common SEO tactics include:
- Keyword research: Identifying and analyzing the search terms target audiences use
- Content creation: Creating quality content that meets your target audiences’ needs
- Link building: Getting other websites to link to your site so that it appears more trustworthy
- Technical SEO: Improving the technical performance of your site for users and search engines
Why is SEO important?
SEO is important because it can improve your organic visibility in the SERPs, which can translate to more brand awareness and website traffic (and ultimately more sales).
Here are 11 reasons why SEO matters:
1. Search engines generate lots of traffic
Search engines generate lots of traffic, and ranking well means capturing a share of it.
People use search engines to perform billions of searches every day (approximately 16.4 billion per day on Google alone).
And our research on how AI shapes traffic channels shows that organic search generated over one trillion visits in 2025, more than any other channel.
AI traffic is growing faster than anything else, up 66% that year, but from a much smaller base: under one billion visits per month, against tens of billions from organic search.
That means if you don’t capture the clicks available in your niche, your competitors will.
Want an idea of how much organic search traffic you could get? Analyze your competitors’ organic traffic with Semrush’s Organic Rankings tool.
Head to the tool and enter a rival domain. Then, choose your target country and click “Search.”
The “Traffic” section estimates how much organic traffic your competitor will get in the next month.
In the graph underneath, you can see how their organic traffic has changed over time.
Next, go to the “Competitors” tab.
The graph shows which sites compete with your rival the most in search results. And how much organic traffic they get per month.
This can give you a better understanding of the traffic available in your niche.
Scroll down to find more results in the “Organic Competitors” table.
2. SEO can be highly cost effective
SEO can be more cost-effective than paid channels like ads because a well-ranking page can keep earning visibility for months or years without ongoing ad spend — you’re not paying per click or per impression to show up on the results page.
Instead, your main costs are creating the content, updating it over time, and maintaining your site.
And once you’ve achieved high visibility, it’s possible to maintain it with relatively little effort (compared to channels like digital PR and social media).
ForeFront Web, a digital agency, helped Arc Solutions grow organic traffic from roughly 4.1K to 12.4K monthly visits between 2025 and 2026. Organic keyword visibility grew by more than 103%. Traffic has kept climbing since.
3. Search visibility drives brand awareness and authority
Search visibility drives brand awareness and authority as your audience will consistently see your brand if you frequently appear in the search results.
For example, searchers learning a new language are likely to discover Duolingo quickly because the site ranks highly for thousands of topical keywords, as shown by Semrush’s Organic Rankings tool:
Even if they don’t click Duolingo’s results, many searchers will develop an awareness of the brand. And after repeated exposure, they may perceive the brand as authoritative and trustworthy.
Both factors increase the chance that they engage with Duolingo in the future.
To get an idea of your potential reach through search, use Semrush’s Keyword Magic Tool.
Enter a simple term related to your business. Then type your domain, choose your target country, and click “Search.”
The tool will find “Broad Match” keywords that contain your starting term or a close variation.
The “Volume” column shows the average number of monthly searches for each keyword. So, it gives you an idea of the top results’ potential reach.
The personal difficulty score (PKD%) helps you understand your potential to rank highly. It measures how hard it’ll be for your domain to rank on Google’s first page of results, on a scale of 100.
If you rank beyond Google’s top 10 results, few searchers will see your link.
4. Your competitors are (probably) doing it
If your competitors are using SEO, they’ll be getting visibility that your business should be competing for.
And if your competitors aren’t optimizing for search, you have a great opportunity to dominate the search results in your niche.
You can compare your rankings against competitors’ with Semrush’s Keyword Gap tool.
Enter your domain and the domains of up to four competitors, making sure “Root domain” and “Organic keywords” are selected alongside each.
Then, choose your target country and click “Compare.”
Scroll down to the table and select “All” to see all search terms these sites rank for organically.
Then, use the corresponding columns to compare your domain’s rankings against competitors’.
5. SEO complements Google Ads
SEO complements Google Ads as you can rank both organically and in paid positions to occupy more visibility in the SERPs.
PPC ads usually appear at the top of the SERP, meaning they get more visibility than organic results.
But a meta-analysis from FirstPageSage shows that the top five organic results receive significantly more clicks overall than paid ads for the same queries.
So if you have both kinds of results, you get the best of both worlds.
Here’s an example of a brand with a sponsored result and an organic result on the same SERP:
6. Reach prospects throughout the buying journey
SEO lets you reach prospects throughout the buyer’s journey because people turn to search engines at every stage, from early research to final purchase decisions.
For example, mattress brand Casper has a mattress size comparison guide that gets 164.6K organic visits per month, according to the Organic Rankings tool:
The keywords for this page have a mix of informational and commercial search intents (the reason behind a search). That means some people visiting this page are close to buying, while others might be in the market for a mattress later.
Generally, people use different types of keywords at each stage of the buying journey:
- Informational keywords are used to find information, commonly in the earliest stages of the buying journey
- Commercial keywords are used to research products or services, typically in the consideration stage
- Navigational keywords are used to find specific pages, commonly in the decision stage
- Transactional keywords are used to complete specific actions like purchases, typically in the decision stage
When you do keyword research in Semrush, you can find the keyword’s category in the “Intent” column.
For example, here are some results from the Keyword Magic Tool:
Knowing a keyword’s intent helps you tailor your page with information the searcher needs depending on where they are in the buyer’s journey.
7. Optimization efforts can improve the user experience
Optimization efforts can improve the user experience as many important SEO tactics are rooted in website best practices.
And a good user experience can help your conversion rate.
Essentially, Google wants to rank pages that leave its users happy. So you must create user-friendly content in order to succeed.
For example, Core Web Vitals (a collection of website metrics that measure your site’s usability) affect your performance in Google:
- Largest Contentful Paint (LCP): How long it takes for the largest content element on the page to load
- Cumulative Layout Shift (CLS): Measures how much the page layout moves around unexpectedly as it loads
- Interaction to Next Paint (INP): The longest time it takes for the page to display visual confirmation of a successful interaction (e.g., for a menu to open)
Optimizing these metrics can help you rank higher and improve the experience for users on your website.
Use Google’s PageSpeed Insights to review your site’s Core Web Vitals (among other performance metrics). Enter a page’s URL and click “Analyze.”
You’ll get a Core Web Vitals assessment, including a list of specific issues to fix on that page.
Fix each suggestion or have a developer help if you’re unsure how.
8. Keyword research lets you monitor market trends
Keyword research for SEO lets you monitor market trends that can guide your product strategy, marketing campaigns, and more.
For example, Semrush’s Keyword Overview tool shows that searches for “ballet sneakers” have grown over recent months:
So, if you were a footwear retailer, you might decide to start stocking this style of shoe. Or create content about the best alternatives.
9. SEO results are quantifiable
SEO results are quantifiable (you can measure your organic rankings, traffic, and conversions), which helps you gauge your performance and determine whether any adjustments are necessary.
It also means you can prove the importance of SEO for your business.
The best way to monitor your Google rankings is with Semrush’s Position Tracking tool.
The “Overview” report has a visibility graph that makes it easy to track your overall performance. You can also add your competitors’ domains to see how they compare.
- A score of 100% means the site has the top organic ranking for all tracked keywords
- A score of 0% means the site ranks outside the top 100 for all tracked keywords
Scroll down to see a full keyword breakdown.
The “Pos.” columns show each domain’s ranking position(s) on the specified dates. If you see an icon, that means the site ranks for a SERP feature (a special element on the search results page).
You can track organic traffic, organic conversions, and many other SEO metrics with a website analytics tool like Google Analytics 4.
10. SEO helps you protect your brand
SEO helps you protect your brand because you can control results that come up when people search for your brand.
Let’s say someone publishes a negative blog post about your brand.
If you don’t use SEO, it’s more likely that results like these will rank prominently when people search for your brand. And harm your relationships with potential customers.
11. SEO is the foundation for AI search visibility
SEO is the foundation for AI search visibility because the same work that earns rankings also earns citations in AI answers.
The evaluator has changed, from the human clicking the link to the AI composing the answer, but the fundamentals that earn visibility haven’t: structured content, authoritative sourcing, and clear signals about what a page is actually about.
Optimizing for those AI answers is called answer engine optimization (AEO). It shares those fundamentals with SEO, but a few things work differently:
- Direct answers matter more. AI systems tend to pull from content that answers a question plainly and early, rather than content that builds up to the point. Burying your answer under three paragraphs of setup may cost you a citation, even if the page ranks well organically.
- You’re writing for query fan-out, not a single keyword. AI systems often break a single prompt into multiple related sub-queries behind the scenes to build an answer. That means a page optimized around one exact-match keyword can miss the broader set of questions the AI is actually trying to answer around that topic.
- Category entry points (CEPs) are a useful anchor. CEPs start from the real-world situations that make someone think of your category in the first place. Using both together — keywords to find what people are searching, CEPs to capture the moments that lead them there — gives AI systems and search engines ways to recognize and cite your content.
The Content Optimizer in Semrush’s Content Toolkit scores your content for AI and search engines and gives suggestions to help improve each one. This way, you know that your content is optimized for both places.
Finally, monitor your AI visibility with Semrush’s Visibility Overview report, where you can track citations, mentions, visibility, prompts, and more.
Start building your SEO strategy
SEO is one of the highest-return investments in digital marketing because rankings compound. The content you optimize today keeps earning visibility months and years later, rather than stopping the moment you stop paying for placement.
That visibility now spans more than organic results. A site with strong SEO also tends to perform better in AI Overviews, AI Mode, and AI search platforms like ChatGPT and Perplexity.
The overlap matters more than ever. Search is no longer a single results page — it’s a set of surfaces, and searchers now move between them within the same buying journey, sometimes starting a query in ChatGPT and finishing it in Google, or vice versa.
And a brand with strong SEO fundamentals is well-positioned to show up wherever that journey happens to take them.
Ready to improve your SEO and online visibility?
