Answer engine optimization: 6 AI models you should optimize for

AI-powered search is drastically changing the way people find information. For years, ranking well in Google and Microsoft Bing has been the foundation of search visibility.

But as AI-driven search gains traction, is that ranking priority shifting or staying the same? 

We’re in an era of uncertainty we haven’t seen since the early days of SEO – when search engines rose and fell in a battle for relevance.

Time will tell which AI answer engine wins the game. SEO is still relevant, but AI is rewriting the rules.

This article will break down: 

• Six AI search players to watch and how they source content.
• Market share and usage trends that show where search behavior is shifting.
• How AI answer engines still depend on traditional search engines.
• What businesses should do now to optimize for AI-driven search.

 Here’s what you need to know.

AI models and real-time search 

Before we move forward, a quick note on how these AI platforms generally work. AI models are trained on data available up to specific cutoff dates. 

For instance, Google’s Gemini 2.0 Pro had a knowledge cutoff in August 2024, while OpenAI’s GPT-4o extended its training data up to June 2024. Yes, it can change daily.

This means that for recent events or emerging trends, among other things, these models rely on real-time data retrieval rather than their internal knowledge base. 

In other words, their ability to provide accurate and up-to-date results is directly tied to their ability to access and process new information from the web. That is key.

Another thing to note is that AI search engines can build their own web indexes. 

For instance, Perplexity AI’s PerplexityBot crawls the web directly, creating its own content database rather than relying on Google’s or Bing’s indexes. But even so, AI search engines can and do still rely on search engine results, too.

Website owners who want to control how AI search engines access their content can manage these crawlers in their robots.txt settings.

Now let’s discuss the different ways AI search engines are relevant to SEO today.

Google: AI Overviews

AI Overviews represented a huge shift in Google Search.  

Google’s AI-generated responses – powered by Google’s Gemini AI model – are designed to provide quick but comprehensive answers by pulling information from multiple sources.

For SEO professionals, this introduced both opportunities and challenges. 

AI Overviews rely on Google’s search index to determine what information to present, but they also change how users interact with search results.

How AI Overviews work

• Google’s Gemini 2.0 AI model powers AI Overviews, generating instant summaries for certain queries.
• AI-generated responses appear at the top of Google’s search results, often before traditional organic listings.

Market share and adoption

• Google still dominates the search market, holding about 87.28% of the U.S. search market.
• With billions of searches per day, AI Overviews have the potential to reshape organic search traffic and user behavior.

What this means for SEO

• Ranking in Google still matters – AI Overviews primarily pull from the search results.
• A study by Rich Sanger and Authoritas found that 46% of AI Overview citations come from the top 10 organic search results.
• Anecdotal data from my SEO agency suggests you need to be in the top 20 for a better chance of inclusion in AI Overviews. There are outliers, and some resources cited in AI Overviews will rank outside of what we would traditionally call “being ranked at all.” 
• Inclusion in AI Overviews can boost clicks to the cited sources and, according to some research, harm performance for those that don’t show up. For instance, for transactional queries, webpages included in AI Overviews had 3.2 times as many clicks as pages that were excluded. For informational queries, webpages with a presence in AI Overviews had 1.5 times as many clicks compared to webpages excluded by AI Overviews.
• If your content doesn’t rank well in Google, it’s unlikely to appear in AI Overviews, reinforcing the need for strong SEO. There are many opinions on which tactics you need to succeed. I advocate continuing to stay the course with a strong SEO program with a balanced mix of technical SEO, on-page optimization and excellent content.
• Website owners can control whether their content is included in AI-generated answers. Google-Extended is an opt-out setting that allows websites to block Google from using their content for AI models like Gemini, while still allowing Googlebot to crawl their site for search rankings. Blocking Google-Extended won’t affect your rankings in Google Search, but it will stop Gemini from using your content in AI-generated responses. 
• Take note: Research shows that inclusion in AI Overviews can be more volatile than the organic search results. 

Takeaway: AI Overviews aren’t replacing traditional search, but they are changing how search results are consumed. For now, the strategy remains the same: Optimize for Google Search, and AI Overviews will follow.

Google: AI Mode

In March 2025, Google announced AI Mode, an optional feature designed to offer a more AI-driven search experience. 

Unlike standard Google Search, where AI Overviews appear alongside organic results, AI Mode allows users to toggle into a search environment where AI-generated answers take center stage.

How AI Mode works

• A separate search option where AI-generated responses are more detailed, conversational, and visually enhanced. Reminiscent of Bing’s Copilot toggle.
• AI Mode “brings together advanced model capabilities with Google’s best-in-class information systems, and it’s built right into Search. You can not only access high-quality web content, but also tap into fresh, real-time sources like the Knowledge Graph, info about the real world, and shopping data for billions of products. It uses a ‘query fan-out’ technique, issuing multiple related searches concurrently across subtopics and multiple data sources and then brings those results together to provide an easy-to-understand response,” according to Google (announcement link above). 
• Google told Search Engine Land that, like AI Overviews, AI Mode surfaces relevant links to help people find webpages and content, and that Google teaches the model to decide when to include hyperlinks in the response. For example, if it’s likely that users want to take action on a website (like booking tickets), then links would be useful. AI mode will also decide when to prioritize visual information, such as images or videos, for queries like how-to searches.

What this means for SEO 

• Google says that AI Mode “is rooted in our core quality and ranking systems, and we’re also using novel approaches with the model’s reasoning capabilities to improve factuality. We aim to show an AI-powered response as much as possible, but in cases where we don’t have high confidence in helpfulness and quality, the response will be a set of web search results.”
• AI Mode is now in testing. Whether it will impact click-through rates in the same way as AI Overviews remains to be seen. 

Takeaway: AI Mode signals an ongoing shift towards AI-dominated search results. For now, we can assume that the importance of ranking well in traditional search remains the same.

Dig deeper. Google’s AI Mode: Here’s what matters for SEOs and marketers

Google: Gemini

Gemini is Google’s competitor to ChatGPT and other generative AI tools. Gemini functions as both an independent chatbot and the power behind AI Overviews in Google Search.

Over the coming months, Google plans to upgrade virtually all Assistant-enabled devices – from phones to smart home gadgets – to use Gemini as the default assistant.

This shift shows Google’s long-term commitment to AI as a core part of search and user interactions.

How Gemini works

• Gemini pulls from Google search results and third-party content partners (for example, AP) to generate responses, integrating search rankings into its answers. 
• Gemini can also personalize results based on a user’s Google search history, YouTube activity, and app usage, making responses adaptive rather than purely search-driven.

Market share and adoption

• According to Statista, Gemini ranks No. 3 on the most downloaded gen AI apps globally as of January 2025, with approximately 9 million downloads.
• Similarweb data shows that the majority of users are aged 25 to 34 (approximately 30%), with the second highest usage among 18- to 24-year-olds at about 21%.

What this means for SEO

• Ranking in Google Search is still crucial, but there’s more. Gemini pulls from Google’s search index, but it also sources data from content partnerships.
• Consider content that’s optimized for natural language queries, structured data to help enhance context and education-focused content (where teaching something is front and center).
• When Gemini personalizes responses based on user history, visibility in Gemini answers may vary between users. For example, if a user frequently engages with a particular brand’s YouTube channel, Gemini might be more inclined to mention or draw from that brand’s content when that user asks a related question. 
• Click-through rates from Gemini remain uncertain, as Gemini doesn’t always provide direct links. Gemini comes in third for referral traffic as compared to ChatGPT and Perplexity, according to one study. 

Takeaway: Visibility in Gemini means business as usual in terms of having an excellent site that can rank in Google Search, but it also adds complexity with Gemini’s AI-driven personalization and conversational search trends. 

Microsoft: Bing Copilot

Bing was the first major search engine to integrate AI directly into its results, launching Bing Copilot (formerly Bing Chat) in February 2023. It’s no surprise Bing beat Google here, as Microsoft has been a big investor in OpenAI since 2019.

How Bing Copilot works

• Powered by Microsoft’s Prometheus model, which builds on OpenAI’s GPT-4.
• Generates AI summaries based on real-time Bing search results and external data sources.
• AI-generated responses appear at the top of search results, sometimes before traditional web listings.
• You can also click on “Deep Search” for more in-depth AI-powered answers. These answers are also linked to sources found on the web. 
• In addition, there’s a Copilot toggle in Bing for a more interactive, fully powered AI search mode.

Market share and adoption

• Bing accounts for about 7.48% of the U.S. search market.
• While small compared to Google, it’s possible that Bing’s market share may grow more in the future due to its early adoption of AI-powered search and the reliance of other AI platforms on Bing results.

What this means for SEO

• Unlike Google’s AI Overviews, Bing Copilot is more likely to cite sources outside the top-ranked pages, but ranking higher still increases the likelihood of inclusion.
• A study by Rich Sanger found that over 70% of URLs included in Bing Copilot summaries rank in the top 20 Bing search results.
• Bing may present a growing opportunity as AI search adoption increases. 

Takeaway: Bing may no longer be just an afterthought in many companies’ SEO strategies. You’ll want to continue to have a robust SEO program that takes into account ranking signals for Bing.

OpenAI: ChatGPT Search

ChatGPT search is OpenAI’s initiative to enhance traditional search by integrating AI-powered real-time web search into ChatGPT. 

It was initially launched as the SearchGPT prototype in mid-2024 and later integrated into ChatGPT, allowing users to access live search capabilities rather than relying solely on pre-trained knowledge.

By October, OpenAI fully integrated SearchGPT into ChatGPT, enabling it to perform real-time web searches and provide more current, sourced information for user queries.

This positioned ChatGPT search as a direct competitor to traditional search engines, offering users an AI-powered alternative to platforms like Google and Bing. 

But here’s the kicker: It still relies on search engine results.

How ChatGPT search works

• Powered by a fine-tuned version of GPT-4o, post-trained using synthetic data-generation techniques. This includes distilling outputs from OpenAI’s o1-preview model, meaning some responses are AI-synthesized rather than directly retrieved from the web.
• SearchGPT pulls data from multiple sources, including third-party search providers like Bing and direct content partnerships that supply proprietary information.

Market share and adoption

• ChatGPT is the most widely used text generation AI tool, holding nearly 20% of the global generative AI user share in 2023, according to Statista.
• ChatGPT’s weekly active user base doubled in six months, with 400 million weekly active users now relying on its search capabilities, according to TechCrunch.

What this means for SEO

• Since SearchGPT relies on Bing’s indexing system, ensuring your content ranks in Bing is essential. Content not indexed by Bing is unlikely to appear in SearchGPT’s responses. 
• Chatter in the SEO industry suggests that SearchGPT might favor trusted, high-ranking sources in Bing but that it also relies on sources outside the top rankings in Bing.
• SearchGPT’s responses can include clickable sources, potentially driving traffic back to a site. A study analyzing traffic data from 391 SMB websites found that ChatGPT’s referral traffic increased by 123% between September 2024 and February 2025, making it the largest referrer among AI-driven search engines during that period. Additionally, ChatGPT has been sending more traffic to education and technology sites, with more than 30,000 unique domains receiving referrals by November 2024.
• The conversational nature of ChatGPT is changing how users search and consume information. Continuing to emphasize helpful content can only make a website more competitive. 
• In the early days of SEO, search engines were highly susceptible to simple manipulation tactics. Similarly, ChatGPT’s AI-powered search may be vulnerable to manipulation, with tests showing that it could be influenced to return misleading or biased results.

Takeaway: ChatGPT could be the biggest threat to search engine usage. However, SearchGPT’s reliance on Bing means SEO strategies must prioritize Bing to improve the chances of being surfaced in AI-generated results as well.

Perplexity AI 

Perplexity AI is an independent, AI-powered search engine that blends large language models with real-time web data to provide concise AI-powered responses with direct citations. 

The citations piece is probably one of the more compelling things about Perplexity. 

In an interview with Lex Fridman, Perplexity’s founder Aravind Srinivas said:

• “When I wrote my first paper, the senior people who were working with me on the paper told me this one profound thing, which is that every sentence you write in a paper should be backed with a citation, with a citation from another peer-reviewed paper, or an experimental result in your own paper. Anything else that you say in the paper is more like an opinion.
• “It’s a simple statement, but pretty profound in how much it forces you to say things that are only right.
• “We took this principle and asked ourselves, what is the best way to make chatbots accurate, is force it to only say things that it can find on the internet, and find from multiple sources.” 

Launched in late 2022, it has positioned itself as an alternative and direct competitor to traditional search engines like Google. 

How Perplexity works

• Perplexity AI operates as an independent search engine, actively crawling and indexing the web to provide real-time, AI-generated responses to user queries. 
• Instead of building a massive index like Google’s, Perplexity prioritizes indexing high-quality, frequently searched topics based on user behavior. By focusing on trusted and helpful sources, it optimizes for accuracy and truthfulness while maintaining efficiency.
• Each response includes direct source links, differentiating Perplexity from AI chatbots that provide answers without attribution.

Market share and adoption

• Perplexity reportedly had 15 million monthly active users by early 2024. 
• While still small, Perplexity holds approximately 6% of the AI search market—and growing.
• Backed by investors like Jeff Bezos and NVIDIA, Perplexity’s valuation jumped from $500 million to $9 billion in under a year. 

What this means for SEO

• Perplexity relies on trusted sources from the web. This means you must have an authoritative presence on the web.
• One study showed that 60% of Perplexity citations overlap with the top 10 Google organic results.
• Other research indicates that Perplexity has a group of favored, authoritative sources on the web to pull from.
• Because Perplexity is an independent search engine, ranking factors will be different from Google or Bing. 
• Content formatted in a certain way may have a leg up, including clear headings, well-organized sections and succinct answers like FAQs embedded in your content—all of which can be quickly understood and extracted by Perplexity’s model.​
• While Perplexity links to sources, data suggests referral traffic is still quite low. 

Takeaway: Perplexity AI is another contender that could continue to gain traction in AI search and take users away from major search engines. It’s important to remember that it still relies on sources across the web, making an authoritative site with the right content optimized for AI an important step in visibility. 

The future of AI search and SEO

While some predict that the rise of AI will reduce search engine volume significantly (Gartner predicts a 25% drop by 2026), the importance of having a reputable website with trustworthy, optimized content remains critical for the foreseeable future. 

Time will tell which AI wins the game. With many AI platforms facing legal challenges (like Google’s AI Overviews and Perplexity’s lawsuits), legal decisions will also likely shape the winners and how AI search ultimately operates.

So, which AI search engine should you optimize for right now? 

I suggest gathering research on the potential for referral traffic and the audience demographics using the AI search engine. Does it align with your industry and business? 

For those AI search engines that require “extra SEO effort” on top of what you’re already doing, make sure it’s worth it. Track your referral traffic to see if any patterns emerge.

We know that Google is the dominant search engine, so continuing to optimize for Google is key. 

The situation is not perfect, however. While some websites report clicks are up from things like AI Overviews, others are losing big time.

For example, research shows that for queries where AI Overviews appeared in Google, organic CTR fell sharply from 1.41% to 0.64% year over year. 

On the other hand, a different study looking specifically at AI search engines like ChatGPT, Perplexity, and others found that they send 96% less referral traffic to news sites and blogs than traditional Google Search.

Emarketer data echoes this:

Some data already suggest a basic hierarchy of referral traffic coming from certain AI search engines. 

For example, one study found ChatGTP to be a clear winner in referral traffic overall, but things fluctuate based on industry.

Image credit: “SMB websites see rising traffic from ChatGPT and other AI engines,” William Kammer, Search Engine Land

As we continue to see all this play out, we can relax knowing that the fundamentals of SEO are not going away. 

Yes, the approach may change, but the foundation is the same: Put the user first, make a great website that’s optimized for the platforms your target audience uses, and continue to adapt to the different ways you can remain visible in search.