As 2025 winds down, the generative AI sector is witnessing a fascinating redistribution of web traffic, with OpenAI's ChatGPT ceding ground in relative terms while maintaining absolute dominance through sheer user scale.
According to Similarweb's latest Global AI Tracker report, released in early December 2025, ChatGPT's share of generative AI website traffic has fallen from 87.2% a year ago to 68.0% as of December 5, reflecting increased competition from rivals like Google's Gemini.
Yet, this relative decline masks explosive overall growth: ChatGPT now boasts over 800 million weekly users, up significantly from prior benchmarks, inching toward OpenAI's ambitious goal of 1 billion users - initially targeted for 2025 but now projected for 2026 amid media clarifications.
This dynamic underscores a maturing market where ecosystem integration and passive exposure are challenging deliberate user choice.
ChatGPT's Enduring Lead Amidst Share Erosion
ChatGPT's traffic dominance has eroded steadily throughout 2025. Similarweb data shows its share dropping from 78.6% six months ago to 72.3% a month prior, settling at 68.0% by early December. This slide coincides with broader industry fragmentation, as new entrants capture mindshare.
However, absolute metrics tell a triumphant story: global monthly active users (MAU) climbed 180% year-over-year to 810 million by November 2025, with weekly users surpassing 800 million - a milestone highlighted in OpenAI's State of Enterprise AI report. Engagement remains robust, though U.S. time spent per user dipped 22.5% since July, signaling potential saturation or competition pull.
OpenAI's growth trajectory aligns with its enterprise push: over 1 million business customers now use its tools, with ChatGPT Enterprise seats surging 9x year-over-year.
The platform's adoption in lower-income countries outpaced high-income ones by 4x in early 2025, broadening its global footprint. Despite the traffic share dip, referral visits from AI platforms overall ballooned to 1.1 billion in June 2025, up 357% year-over-year, benefiting incumbents like ChatGPT.
Gemini's Meteoric Rise: Distribution Over Destination
Google's Gemini has been the standout gainer, vaulting from 5.4% traffic share a year ago to 18.2% by December 2025 - a 12.8-point increase. Monthly active users swelled to 346 million by November, a 30% jump from August, far outpacing ChatGPT's 5% growth in the same period. Earlier estimates pegged Gemini at 350 million MAU in March, escalating to over 400 million by May and potentially 650 million visits by late year, though exact figures vary.
This surge isn't purely organic; it's fueled by Google's ecosystem dominance. AI Overviews, now reaching over 2 billion monthly users across 200+ countries and 40 languages, funnel queries into Gemini's AI Mode for follow-ups. Users can't disable these overviews, ensuring passive exposure.
On Android - commanding 70%+ of global smartphones - Gemini is the default assistant, converting billions of existing users without deliberate seeking. Tellingly, 76% of Gemini's traffic originates from google.com, indicating encounters during routine searches rather than targeted visits.
Product innovation bolsters this: NotebookLM, upgraded with Gemini 3, remains unparalleled for research synthesis, allowing notebook exports to Sheets and podcast-style audio overviews.
Viral hits like Nano Banana (23 million first-time users, 500 million images in two weeks) and Gemini 3 Pro's accessible explanations have spawned memes and organic buzz. Gemini supports 180+ countries and, by October 2025, attracted 206.4 million unique visitors - a 69% rise from August.
The Broader Field: Grok, Claude, and Emerging Players
While ChatGPT and Gemini dominate, others are nibbling shares. xAI's Grok climbed to 2.9% from 2.1% six months ago, buoyed by Grok-4.1's release. Anthropic's Claude hit 2.0%, surpassing Perplexity (2.1%) for the first time, reflecting its coding prowess. Microsoft's Copilot stagnated at 1.2%, despite Windows integrations, highlighting that distribution alone isn't enough without compelling features. DeepSeek held at 3.9%, while niche tools like Hugging Face and Meta AI captured smaller slices.
Overall, generative AI traffic is no longer monopolistic, with fragmentation benefiting users through choice. For brands, this means optimizing for multiple AI referrals, as platforms generated 1.1 billion referrals in June 2025 alone.
2026 Outlook: Sustaining Momentum in a Fragmented Arena
Can these titans maintain their edge? OpenAI's path to 1 billion users hinges on innovations like GPT-5 and Deep Research, but slowing growth (5% MAU rise Aug-Nov) suggests competition is biting.
Google's distribution moat - evident in Gemini's 155% YoY desktop user growth versus ChatGPT's 23% - positions it for ambient AI dominance, potentially monetized via Pro/Ultra subscriptions. Yet, if AI evolves into deliberate tools, ChatGPT's brand loyalty could prevail.
As Similarweb notes, this isn't a zero-sum game: the pie is expanding, with Gen AI moving from novelty to utility. We'll revisit in a year - perhaps with Grok or Claude claiming larger slices. For now, 2025's data reveals a market in flux, where integration trumps isolation.
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Author: Slava Vasipenok
Founder and CEO of QUASA (quasa.io) - Daily insights on Web3, AI, Crypto, and Freelance. Stay updated on finance, technology trends, and creator tools - with sources and real value.
Innovative entrepreneur with over 20 years of experience in IT, fintech, and blockchain. Specializes in decentralized solutions for freelancing, helping to overcome the barriers of traditional finance, especially in developing regions.
