Mark Williams-Cook on SEO Updates 1 June 2026
Why Mark Williams-Cook Wrote This
Mark Williams-Cook publishes this weekly SEO news roundup every Monday for his audience of SEO professionals and website owners. The June 1 edition covers a particularly active week, with major updates from Google, OpenAI, the EU, and independent researchers all landing at once.
The post also promotes his Core Updates newsletter and a new podcast episode featuring Chris Green’s independent study on the correlation between rankings and People Also Ask questions.
Mark’s key points from June 1, 2026
Google adds Preferred Sources to AI search
Users can now choose their favourite websites to highlight inside Google’s AI search results. Selected sources can appear within AI Overviews and AI Mode, giving chosen publishers a visibility advantage.
From Google Discover, now in SearchAI Overviews appear in 86% of prompts
A Peec AI study of 500,000 prompts found AI Overviews appear in more than 86% of Google queries. Critically, this includes commercial queries, not just informational ones.
Via Tomek Rudzki / Peec AIAI Overviews increase time spent on SERPs
When AI Overviews are present, user time on the search results page rises and converges regardless of search intent. This suggests people are reading AI answers rather than clicking through immediately.
Via Eric Van BuskirkChatGPT referral traffic up 150%
Since ChatGPT made its links more prominent on May 7, 2026, referral traffic from ChatGPT to websites increased by 150%. Link prominence in AI answers directly drives clicks.
Via Barry SchwartzGoogle adds new personalisation settings
Two new settings launched: Saved Media lets your saved files influence search results, and Personalised Recommendations controls whether results are customised to your behaviour and history.
Via Abner LiOpenAI search crawler updated to v1.4
OpenAI’s web crawler now uses the user agent OAI-SearchBot/1.4. Website owners should check server logs and update robots.txt if they want to control whether their content appears in ChatGPT search.
Via Tom PoolGoogle launches agent-friendliness audit tools
A new WebMCP audit tool and an ‘agentic-browsing’ Lighthouse category help website owners understand how accessible their pages are to AI agents. The tools check accessibility, schema, forms, and other elements.
Google Lighthouse updateMerchant Center adds AI-ready product attributes
Google Merchant Center added optional conversational attributes to product feeds. Adding these new fields can help products appear in conversational AI queries and shopping agents.
Via Bastian GrimmWhat Mark Williams-Cook Found
The 10 updates span AI search, personalisation settings, developer tools, e-commerce, maps, and legal news. Here is each one broken down:
| Update | What it means | Source |
|---|---|---|
| Google Preferred Sources in AI Search | Users pick favourite sites to highlight in AI Overviews and AI Mode | |
| AI Overviews in 86% of prompts | Study of 500,000 prompts shows near-universal AI Overview presence, including commercial queries | Tomek Rudzki / Peec AI |
| AI Overviews increase SERP time-on-page | User time spent on search results pages rises and converges when AI Overviews appear | Eric Van Buskirk |
| ChatGPT referral traffic up 150% | Prominent links added May 7 drove a 150% increase in clicks from ChatGPT to websites | Barry Schwartz |
| Google personalisation settings added | Saved Media and Personalised Recommendations now let saved files and preferences shape results | Abner Li |
| OAI-SearchBot/1.4 crawler update | OpenAI’s search bot has a new user agent string; update robots.txt to control access | Tom Pool |
| Google WebMCP audit tool and Lighthouse update | New tools help diagnose how agent-friendly a page is by checking accessibility, schema, and forms | |
| Google Merchant conversational attributes | Optional new product feed attributes help items appear in conversational AI queries and shopping agents | Bastian Grimm |
| Google Maps Street View interactive spaces | Project Genie creates interactive spaces from real locations; available in Google Labs for AI Ultra subscribers | |
| EU antitrust fine and US DOJ appeal | EU plans a record fine under the Digital Markets Act; Google filed a 111-page appeal of its US monopoly ruling | News sources |
The AI Overviews data point from Peec AI stands out. A figure this high means that whether your content targets someone searching to learn something or to buy something, an AI Overview is almost certainly appearing above your organic result.
The ChatGPT referral traffic finding from Barry Schwartz adds to this. The jump in clicks after May 7 shows a direct connection between how prominently links appear in an AI answer and how much traffic they send. Visibility inside AI outputs is now a practical traffic driver, not just a branding consideration. For more on tracking this for your own site, resources like AllINeedForMyWebsite.com cover AI traffic and SEO strategy in depth.
What This Means for Your Website
AI Overviews appearing in 86% of prompts means your content is competing for AI citation on nearly every query type, not just informational ones. If your product or service pages are not structured clearly enough for AI systems to extract and cite, you are missing visibility on commercial queries where intent is highest.
The OpenAI crawler update is a quick, practical action item. Check your server logs for the old OAI-SearchBot string and update your robots.txt to allow or block the new OAI-SearchBot/1.4 user agent based on whether you want your content appearing in ChatGPT search results.
Action to take now: Open your robots.txt file and add or update a rule for OAI-SearchBot/1.4. If you want ChatGPT to index your site, allow it. If you want to block it, add a disallow rule. Either way, check your server logs first to see how often the bot is already visiting.
Read Mark Williams-Cook’s full LinkedIn post here: linkedin.com/posts/markseo_seo-updates…
Key takeaways
- AI Overviews now appear in more than 86% of Google search prompts, including commercial queries, based on a study of 500,000 prompts by Peec AI.
- ChatGPT referral traffic to websites increased by 150% after OpenAI made links more prominent in answers on May 7, 2026.
- Google’s new Preferred Sources feature lets users highlight their favourite websites inside AI Overviews and AI Mode.
- OpenAI updated its search crawler user agent to OAI-SearchBot/1.4; website owners should review and update their robots.txt accordingly.
- Google Merchant Center added optional conversational attributes to product feeds, helping products appear in AI-driven shopping queries and agent-based searches.
FAQs
According to a study of 500,000 prompts by Peec AI, reported by Tomek Rudzki, AI Overviews appear in more than 86% of Google search prompts. This figure covers both informational and commercial queries, meaning AI Overviews are present across almost all search types.
According to a study of 500,000 prompts by Peec AI, reported by Tomek Rudzki, AI Overviews appear in more than 86% of Google search prompts. This figure covers both informational and commercial queries, meaning AI Overviews are present across almost all search types.
According to a study of 500,000 prompts by Peec AI, reported by Tomek Rudzki, AI Overviews appear in more than 86% of Google search prompts. This figure covers both informational and commercial queries, meaning AI Overviews are present across almost all search types.
ChatGPT referral traffic to websites increased by 150% following a change on May 7, 2026, when OpenAI made links more prominent within AI answers. The data, reported by Barry Schwartz, confirms that the visibility of links in AI responses has a direct and significant impact on click-through rates.
Google’s Preferred Sources feature, originally from Google Discover, lets users select their favourite websites to highlight within Google’s AI search products. Once selected, those sources can appear more prominently inside AI Overviews and AI Mode results.
OAI-SearchBot/1.4 is the updated user agent string for OpenAI’s search crawler, which indexes web content for use in ChatGPT search. Website owners should check their server logs for this new string and update their robots.txt file to allow or block the bot depending on whether they want their content to appear in ChatGPT search results.