May SEO Round-Up: AI Search, Visibility & Industry Shifts

May was another significant month for search and AI, with Google and OpenAI continuing to reshape how users discover information online. From a major Google Core Update and the growing dominance of AI Overviews to new personalisation features and increased referral traffic from ChatGPT, the trend is clear: search is becoming more AI-driven and more focused on delivering answers directly to users.

At the same time, both Google and OpenAI are placing greater emphasis on content quality, trust and visibility, making it increasingly important for businesses to publish genuinely useful information that can be surfaced, cited and trusted across a growing range of AI-powered experiences.

Google Core Update

Google rolled out its latest Core Update between the 21st of May and the 2nd of June, arriving just 43 days after the previous update. If this pace continues, 2026 could see significantly more core updates than usual, potentially increasing from the typical two or three per year up to as many as seven.

The update triggered widespread volatility across search results, with more than 76% of top-ranking URLs reportedly experiencing movement. Much of the focus appears to be on tackling low quality and repetitive AI generated content, while Google continues to place greater emphasis on original, quality content.

We also saw Google further strengthen its evaluation of E-E-A-T signals, particularly across “Your Money or Your Life” topics such as health, finance and legal content. For businesses, the message remains consistent: as AI-generated content becomes more common, Google is placing greater value on content that demonstrates expertise and offers clear value. Simply publishing AI-generated copy with minimal input is becoming a far riskier strategy as search becomes increasingly competitive with AI features keeping more users within the results page. To stand out, businesses need to generate their own content that demonstrates expertise and provides value.

Google Brings ‘Preferred Sources’ Feature to AI Search

Google expanded its ‘Preferred Sources’ feature into AI Overviews and AI Mode on the 27th of May, giving users more control over the sources they see within AI-generated search results. The feature allows users to select websites they trust or regularly visit, with content from those sites highlighted when it appears in AI responses. According to Google, users are twice as likely to click through to a source they have personally selected, making this a notable development in how people interact with AI-powered search.

While the feature is still relatively new, there are already suggestions that Preferred Sources could become more influential within AI Search over time. If Google continues down this path, sites that users actively choose may have a greater chance of appearing in AI-generated responses. More broadly, it reflects Google’s ongoing shift towards personalised search experiences, where individual preferences play a bigger role in what users see. For businesses, this reinforces the importance of building trust and publishing content that people actively want to return to. Consistent, useful and helpful content is becoming increasingly important, not just for rankings, but for building long-term visibility in AI-driven search.

AI Overviews Dominating Google Search Results

AI Overviews are now appearing for an estimated 86% of Google AI Search results, highlighting just how central they have become to Google’s search experience. Since their introduction, Google has continued to expand the prominence and coverage of AI-generated answers, giving users quick access to information without requiring multiple clicks. Combined with newer features such as follow-up questioning through ‘Ask Anything’, users are increasingly able to find what they need directly within the search results page.

For website owners, this trend presents both a challenge and an opportunity. As more users find answers without leaving Google, organic traffic is becoming harder to earn. At the same time, the sites that are cited within AI Overviews can benefit from increased visibility and authority. With Google continuing to refine how it evaluates source quality, businesses should focus on creating original, useful content that demonstrates genuine expertise. The better your content answers a query, the greater the chance it has of being surfaced within Google’s AI-driven search features.

ChatGPT Referral Traffic Increases by 150%

Traffic being referred from ChatGPT to external websites has seen a significant increase, with SimilarWeb reporting growth of around 150% following changes to how links are displayed within responses. On the 7th of May, OpenAI began introducing more prominent, clickable links to brands and websites, making it easier for users to navigate directly to cited sources rather than relying on citation lists or source chips. The change appears to be having a noticeable impact, building on a wider trend of growing referral traffic from AI platforms. Separate data from SEMrush found a 206% year-on-year increase in outbound referral traffic between January 2025 and January 2026.

As AI platforms become a larger source of website traffic, visibility within AI-generated responses is becoming increasingly valuable. Being cited is no longer just about brand awareness; it can directly influence visits to your site. This places even greater importance on publishing useful, trustworthy content that AI systems are likely to reference. It also highlights the need for strong user experience once visitors arrive. If a landing page is slow, difficult to navigate or fails to meet expectations, users are far less likely to engage with the content, regardless of how they found it.

OpenAI Updates Its Search Crawler User Agent

OpenAI introduced clearer guidance in May around the different web crawlers used across its products, giving website owners more control over how their content is accessed and used. The update separates the functions of each crawler, making it easier for webmasters to decide whether they want their content to appear in ChatGPT search results, contribute to AI training, support advertising verification or be accessed during user-requested actions.

The distinction is particularly important as AI platforms continue to play a larger role in content discovery. For example, OAI-SearchBot is responsible for surfacing websites within ChatGPT Search, while GPTBot is used to collect content that may contribute to future model training.

OpenAI has also separated crawlers used for ad verification and user-triggered browsing, helping to provide greater transparency around how content is accessed. For businesses, this serves as a reminder that AI visibility is no longer controlled solely through traditional search engine settings. Understanding which AI crawlers have access to your site, and what they are permitted to do, is becoming an increasingly important part of managing your online presence.

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