Similarweb 2026 Data: AI Search, The D2C Funnel, and Where It’s Reassembling

For eighteen months, Similarweb has tracked generative AI's takeover of consumer search across three reports: the *2025 Generative AI Landscape*, the *2026 Generative AI Brand Visibility Index*, and the *2026 Downstream Impact of AI Visibility* study. Together they document a new, invisible layer sitting on top of the traditional marketing funnel, where a small set of brands wins discovery not because they have better infrastructure than competitors, but because they moved first on citation.

For D2C brands, that layer is unavoidable: 35% of US consumers say they use AI tools at the product discovery stage, versus 13.6% who use search. AI has officially overtaken search as where people start looking. The bigger problem? The current ways of measuring success no longer describe what's actually converting.

Here are some of the key highlights we think are worth mentioning from their 2026 report:

The market fragmented, and the winners aren't who you'd guess

ChatGPT still holds 79% of generative AI traffic as of January 2026, but its share is declining as Gemini and Claude gain ground. Gemini grew 157% in five months to 1.1 billion monthly visits; Claude's unique visitors grew roughly 180% H2 vs. H1 2025. There is no longer one "AI search" to optimize for, and a strategy built around any single platform is already out of date.

Inside that fragmentation, Similarweb's Brand Visibility Index that benchmarks AI citation share across Finance, Travel, Consumer Electronics, Beauty, Fashion, and News, found that AI visibility rank and brand size rank consistently diverge. Apple leads consumer electronics, but specialist retailers like Adorama, Crutchfield, iFixit, and Backmarket are cited by AI far more than their market share predicts. CeraVe outranks bigger beauty brands; NerdWallet and Travelmath outrank category giants in finance and travel. The pattern holds across Similarweb's findings: being the best answer to a specific question beats being the biggest brand in the room. The early-adopter advantage isn't ad spend, but structured, question-answering content published early enough to be indexed and trust before competitors knew there was a layer to win.

Citation and traffic are landing in different places

SEO strategist Aleyda Solis's contribution to the report found that 65% of URLs ChatGPT cites sit two or three folders deep in a site's structure, while 58.8% of AI referral traffic that does click through lands on homepages. AI reads your deep, specific content to build its answer, then sends the few users who click somewhere else entirely. This is a clear sign that GEO strategy can't stop at the homepage.

Clicks are also getting scarcer, not from declining relevance but from AI succeeding at what search increasingly does too. Similarweb's synthesis shows AI platform visits climbing toward 1.5 billion monthly while AI referral traffic has sat flat between 240–280 million a month since mid-2025. Chatbots have become closed-loop research environments where users compare and decide without clicking out, the same zero-click pattern behind 68% of Google searches. Google's referral rate holds at 17–19%; AI Mode's sits at 1.6–2.5%.

The funnel didn't shrink. It went dark.

Similarweb's Downstream Impact study tracked users who got a ChatGPT brand recommendation, left without clicking, then were followed for seven days. Brands ChatGPT mentioned were 2.5x more likely to get a site visit in that window than brands it didn't mention, but 55.9% of that traffic arrived through branded search, not an AI referral link. The conversation that created the intent left no trace; Google got the credit. Those visitors also convert better: roughly 7% versus 5% for other traffic on transactional sites, with nearly double the pages viewed and time on site. The intent AI creates is real and high quality, and it's invisible to a dashboard built to credit the last channel touched.

What this means for D2C marketing

D2C brands are being asked to define "performance" on platforms that fragment faster than any team can instrument, using attribution built for a funnel with visible steps. Brand size is no longer a hedge: the specialists Similarweb highlights prove AI rewards structured authority over scale.

That's the layer eLLMo AI operates in. eLLMo is the agentic layer that helps D2C brands understand and improve how they show up inside agentic commerce, not by guessing at prompts, but by testing pages against real-world psychographic buyer profiles the way AI agents actually evaluate them: what claims get trusted, what's missing, where a segment's hesitation starts. Instead of waiting on a referral line Similarweb's own data shows is structurally flattening, brands get a direct read on their visibility and credibility where discovery now happens first.

The brands that win this next era won't have the biggest budgets. They'll be the ones who treat citation the way they used to treat search rank: a metric to own and compound, starting now, while the rest of the category is still measuring a funnel that's already moved.

*Sources: The 2026 Generative AI Landscape Report, The 2026 Generative AI Brand Visibility Index, AI Search Trends: What Changed In The Past Year, AI-Recommended Brands Saw 2.5x More Site Visits: Similarweb (Search Engine Journal).*