Erosion of Hegemony: Dynamic Shifts in Search and Advertising Market Share
1. The Loosening of Google’s Gateway Status
For over two decades, “Google” has functioned as both a noun and a verb, representing the primary entry point to the internet. However, by 2025, data indicates this status is fracturing. The most significant market signals are Google’s global digital advertising market share falling below 50% and its search engine market share slipping below the 90% threshold.
2. Portfolio Change in the Advertising Market: Breaking the 50% Watershed
According to reports from industry analysts such as Warc and MBI Deep Dives following Q3 2025, Google’s share of the global digital advertising market (excluding China) fell below 50% for the first time. Specifically, from Q3 2021 to Q3 2025, Google lost approximately 760 basis points (7.6%) of market share.
This lost share has shifted precisely to other platforms:
- The Rise of Amazon (+400 bps): Leveraging its absolute advantage in “Transactional Intent,” Amazon captured massive search ad budgets. High conversion rates for product searches on Amazon have made Retail Media the fastest-growing advertising format.
- The Recovery of Meta (+300 bps): Successfully emerging from the shadow of Apple’s ATT privacy policy, Meta utilized AI-driven tools like Advantage+ to enhance ad efficiency, reclaiming budgets particularly in discovery-based and impulsive shopping.
This phenomenon is known as a “Portfolio Change.” Advertisers no longer view Google as the sole essential option, instead allocating budgets based on the marketing funnel: Brand Awareness (YouTube/Meta), Product Discovery (TikTok/Instagram), and Purchase Conversion (Amazon).
3. Search Engine Market: Breaching the 90% Defense Line
StatCounter data shows that as of late 2025, Google’s global search market share has slipped to the 88-90% range, the first time it has consistently stayed below the 90% psychological barrier since 2015.
Global Search Engine Host Market Share (December 2025)
| Search Host | Market Share | Trend Analysis |
| 88.76% | Slow decline due to diversion by vertical platforms and AI chatbots. | |
| Bing | 3.86% | Maintains small growth via Microsoft ecosystem and enterprise advantages. |
| DuckDuckGo | 0.78% | Stable among privacy-sensitive users. |
| Yandex | 0.65% | Regional strength (Russian-speaking markets). |
| Baidu | 0.53% | Regional strength (Chinese market). |
Structural reasons for this decline include:
- Fragmentation of Mobile Behavior: While Google holds 92.5% of the mobile search host market, this does not capture “in-app search behavior,” such as users searching for travel tips on TikTok or restaurants on Instagram.
- Generative AI Substitution: Tools like ChatGPT and Perplexity are diverting “knowledge-exploration” queries. While Google’s volume remains hundreds of times larger than ChatGPT, the loss in high-value complex queries is factual.
4. Technological Disruption: The Rise of Answer Engines
The deepest threat to Google is the shift from a “Search Engine” (indexing and retrieving links) to an “Answer Engine” (understanding and generating information).
4.1 Quantifying the AI Challenge
- ChatGPT’s Scale: ChatGPT processes approximately 887 million “search-like” prompts daily, compared to Google’s 14 billion. The 1:16 ratio highlights that ChatGPT intercepts the most complex, high-value queries.
- Perplexity AI’s Niche: With over 22 million MAUs in 2025, Perplexity has become the preferred tool for knowledge workers seeking ad-free, cited answers.
- Internal Defense: Google’s Gemini App reached 650 million MAUs by Q3 2025, successfully retaining users but facing “cannibalization” risks as AI interactions are harder to monetize than traditional ad links.
4.2 The “Zero-Click” Dilemma and Ecosystem Collapse
The integration of “AI Overviews” (AIO) has improved user utility but triggered a crisis for publishers. Data from September 2025 shows that organic search click-through rates (CTR) plunged by 61% for queries triggering AIO. This “Zero-Click” trend threatens the content ecosystem that fuels AI training data.
4.3 Monetizing AI Interfaces: Ads in AI Overviews
Google is transitioning its “printing press” to the AI era through “Ads in AI Overviews.”
- Contextual Placement: Ads are embedded naturally within AI-generated text (e.g., suggesting a specific vacuum cleaner within a “how-to” guide).
- Higher Engagement: Early data suggests these ads have 3.4 times the engagement of traditional search ads because they appear at the moment of “untapped intent.”