Google’s AI Overviews (AIO) has been a disruptive force in search marketing since its genesis. There have been significant changes in the past, such as the September 2023 HCU update, but none have been so broad or divergent as to overhaul search at scale and impact all websites. However, this didn’t all happen at once. 

AIO has been in a constant state of change since first announced in 2023. The search ecosystem, including website performance, has been reacting to these changes in real time.

Here, we plot the evolution of Google’s AIO, outlining distinct eras of development and mapping key changes to real-world data.

AI Overviews - a timeline

Era 1: The SGE experiment (May 2023 - May 2024)

May 2023 to April 2024 was the most experimental phase in the AIO’s history. Google was trying to figure out how this new product fit among (and impacted) its existing infrastructure, as well as what end-users wanted from such an addition.

Key milestones:

• May 10, 2023 - Google unveils AIO (then called SGE) at Google I/O and opens the waitlist for Search Labs (US only). SGE in search is described as an “AI snapshot”
• May 25, 2023 - Users who signed up to the waiting list are given access to SGE
• August 30, 2023 - 
  • Expansion to India (English and Hindi) and Japan for those opted into Search Labs
  • Google introduces ‘SGE while browsing’, a feature that summarises key points of a web page as digestible bullet points, linking through to specific anchor points in the text where users want to explore source information
• November 08, 2023 - 
  • SGE expands to over 120 countries around the globe for users opted in to Search Labs
  • GDPR and related privacy legislation thought to be the reason why the UK and EU nations were not included in this initial expansion
  • 4 new languages made available in SGE:
    • Spanish
    • Portuguese
    • Korean
    • Indonesian
• March 22, 2024 - In the US, Google begins testing SGE on their SERPs, even for those who did not opt in via Search Labs
• April 4, 2024 - Google starts testing SGE in the UK for a 'small slice' of logged-in users.

The impact context:

During this phase, the threat was theoretical for most UK brands, but the direction things were headed was clear. Organic results would get fewer clicks.

At this stage, AIO favoured content from trustworthy, authoritative sources as opposed to user-generated content, meaning UGC sites like Reddit and Quora were barely cited.

Era 2: Rebrand and rollout volatility (May 2024 - January 2025)

This era was defined by aggressive expansion met with immediate public scrutiny. It was the moment the "AI Snapshot" became the AI Overview we know today.

Key milestones:

• May 14, 2024 - 
  • SGE is officially rebranded as AI Overviews during the 2024 I/O developer conference
  • Google launches full US rollout
• ~ May 18, 2024 - 
  • Glue pizza-gate! Google hits a PR storm as an AI Overview instructs someone to add glue to their pizza to stop the cheese from falling off. Similar occurrences follow.
  • Google reduces AIO frequency globally to work on additional guardrails in response to the controversy
• May 21, 2024 - Google discuss ads in AI Overview publicly for the first time - at their Marketing Live event. They announce that they will begin testing Search and Shopping ads directly within AI Overviews
• August 15, 2024 - 
  • Google expands AI Overviews to the UK, India, Japan, Indonesia, Mexico, and Brazil for all users. This coincided with the rather large August 2024 core update
  • Google begins placing in-line text links to sources in AI Overviews - alongside the existing link cards.      
• October 03, 2024 - In the US, ads begin showing in certain AI Overviews on mobile. Placements are automatic.
• October 28, 2024 - AI Overviews are launched for all users in 100+ countries - the largest full expansion to date

The impact context:

The “glue pizza” incident gave Google pause; AIO frequency dropped to ~9%(1), but the recovery was decisive. By August 2024, Google was aggressively scaling the feature globally, alongside a core update, signalling that AIO was now deeply integrated into ranking systems.

Related - Google algorithm updates - complete history and live changes

Clicks continued to decline, but there was a silver lining for pages ranking on page 2 or below. Even though AIO was building towards citing at least one of the top 10 organic positions 99.5% of the time(2), the total overlap reached as low as 3%.

Rankings were still of utmost importance (AI Overviews weren’t always served, and when they were, users could still scroll down), but this meant you could get position-zero exposure without ranking in Google’s top spots.

Several other shifts emerged:

• Content type disruption: Research showed that 96% of AIO citations were informational(3), meaning blogs, guides, and TOFU content (historically the backbone of SEO traffic) were the most exposed to click loss
• Compression of the consideration phase: With AI Overviews delivering summarised answers instantly, users increasingly completed their research without leaving the SERP.
• Changing query dynamics: By late 2024, AIOs were appearing more frequently for shorter, broader queries, expanding their reach beyond long-tail informational searches.
• Visual dominance and CTR pressure: Confirmed data showed AIO + Featured Snippets could occupy:
  • 67.1% of desktop screens
  • 75.7% of mobile screens(4)
• Early monetisation signals: The introduction of ads within AIOs marked a key turning point. Google was no longer just experimenting with UX but actively protecting and evolving its revenue model

Era 3: Monetisation and “The Great Decoupling” (January 2025 - December 2025)

In 2025, Google shifted from "Will it work?" to "How do we make it pay?", leading to the introduction of ads in AI Overviews. Furthermore, at this stage, the impact of AI Overviews was becoming reliably quantifiable, and the industry began observing what would come to be referred to as “The Great Decoupling”:

Key milestones:

• January 2025 - AI Overviews start pulling information from Google Business Profiles, leading to a steep decline in GBP engagement metrics
• February 24, 2025 - Google tests adding up to 60 links in AI Overviews, raising concerns that this would deter rather than encourage clicks
• March 5, 2025 -
  • AI Overviews was now being powered by Gemini 2.0 in the US
• March 18, 2025 - Google tested having links in AI Overviews trigger a new Google search, giving rise to worries it would further reduce CTR for websites
• Late March 2025 - 
  • Google tests serving AI Overviews mid rather than top of the SERP
  • Googler says AIO changes too quickly to make dedicated measurements in Search Console worthwhile.
• Early April 2025 - 
  • Tracking tools show AI Overviews appearing more regularly than in March
  • Google seen testing in-line links directly in the text of AI Overviews. Welcomed by site owners as a way to boost CTR from AIO.
• May 20, 2025 - Google confirms that AI Overviews are live in 200+ countries in 40+ languages
• May 21, 2025 - In the US, ads in AI Overviews expand to desktop
• Early June, 2025 - Research shows that Reddit was the top-cited source in AI Overviews, reversing earlier patterns showing a lack of UGC citations
• Early July 2025 - 
  • AI Overviews starts powering a fraction of PAA results
  • Report shows zero-click searches increased by over 10% since AIO launch. This was supported by evidence of “The Great Decoupling”, where impressions and clicks move in opposite directions
• October 2025 - Google adds a ‘Show more’ button to some AI Overviews - directing users to an AI Mode search
• December 2025 - Ads in AI Overviews expanded globally

The impact context:

For most, traffic was in sharp decline. Research showed that the presence of AI Overviews reduced organic clicks from 3.97% to 0.64%(5), signalling that user behaviour was changing. Paid performance followed a similar trajectory, showing that the impact of AI Overviews wasn’t limited to organic search.

In many cases, visibility hadn’t disappeared. Impressions often remained stable, and in some instances even increased. However, clicks were less likely to follow. By April 2025, CTR for top organic positions for informational queries was down by 34.5%(6). This downward trajectory applied across organic search as a whole, but authoritative brands could buck the trend with the right approach, insight, and support.

During this period, multiple new robots.txt updates emerged, attempting to give publishers control over how their content was accessed and used by AI, including AIO, but compliance was and remains voluntary.

This era fundamentally changed how SEO performance needed to be interpreted. Tracking tools were unable to capture engagement happening in AI search surfaces like AIO, so legacy SEO metrics were no longer telling the full story. 

The impact was most pronounced for informational queries, where AI Overviews effectively absorbed the role that blog content had historically played. On the other hand, for high-intent, brand-led queries, some studies suggested that AI Overviews could actually reinforce user confidence, leading to increased click-through rates(7).

Many businesses found lower CTR alarming, but not much had changed in terms of actual business performance. Users seeking shallow informational answers were being filtered out of the traffic, meaning the remaining traffic was higher quality.

Era 4 - Personalisation, control, and ecosystem tension (January 2026 - present)

• January 2026 - Google places restrictions on AI Overviews for YMYL queries after an investigation by The Guardian highlights misinformation in health-related overviews
• January 26, 2026 - 
  • AI Overviews is upgraded to Gemini 3.0
  • Google adds light personalisation to AI Overviews, adding more media that the user has engaged with in the past
  • Google adds a ‘Follow up’ button to AI Overviews that directs users to AI Mode for additional research
  • Google says that their systems learn not to show AI Overviews for queries that typically don’t result in engagement with the overview
• February 2026 - AI Overviews get prominent link cards that appear when a user hovers over a citation, a welcome approach expected to increase clicks
• March 2026 - 
  • Google actively developing publisher opt-out controls for their AI search features under pressure from the UK CMA
  • AI Overviews begin decoupling (again) from the top organic results.
  • AI Overviews appearing more frequently - for almost half of all tracked queries(8)

The impact context:

Now, in 2026, AI Overviews appear for nearly half of all queries. Reverting to its original process, citations now regularly diverge from the traditional top organic results, making ranking position an increasingly unreliable indicator of both visibility and traffic. 

Google has introduced refinements that appear to offer more opportunity for publishers, such as in-line citations and hover-based link cards. While these features improve the visibility of sources within AI Overviews, they also reinforce Google’s control over the user journey. Clicks are still possible, but carefully mediated, designed to provide access without encouraging users to leave the SERP too early.

Personalisation is another major evolution in AI Overviews. AIOs may now adapt responses based on prior user behaviour and content engagement, signalling a move away from purely query-driven results toward a more user-centric model. 

This introduces a new layer of complexity for measurement and optimisation, as search results become less consistent across users and harder to replicate or track in a standardised way.

Navigate shifts in Search with TDMP

Search is becoming more opaque, more personalised, and harder to measure with traditional tools. It’s common for businesses to feel as if they have no way of taking back control - but with strategic, AI-aware SEO and Paid Media strategies delivered by those who understand your industry, you can find your footing and begin uncovering the opportunities behind challenges.

At TDMP, we help brands adapt to this new reality, tracking what actually matters, identifying where visibility is gained or lost within AI-driven SERPs, and building strategies that drive real business outcomes. Contact us today to get started.

Citations

1. 10 Observations about AI Overviews after a full month - BrightEdge
2. Mark Traphagen, LinkedIn post - LinkedIn
3. Mark Traphagen, LinkedIn post 2 - LinkedIn
4. AI Overviews Study: Inside Google’s New Search Reality - Botify
5. Google AI Overview Study - SEO & PPC CTR Impact  - Seer Interactive
6. AI Overviews Reduce Clicks by 34.5% - Ahrefs
7. Google AI Overviews: New Study Reveals How to Navigate Negative SERP Impact – Amsive
8. AI Overviews at the One-Year Mark: Presence, Size, and What They’re Citing - BrightEdge