March 9, 2026 — A study by Graphite.io CEO Ethan Smith found that top AI assistants including ChatGPT, Gemini, Perplexity, Grok and Claude generated 45 billion monthly sessions globally in Q4 2025, equating to AI assistants now dominate 56% of global search volume, up significantly and impacting SEO and digital marketing worldwide, as highlighted in coverage from the week of March 7-13, 2026.
The analysis, based on Similarweb data for web visits and mobile app sessions, showed AI accounting for 34% of U.S. search volume with 5.4 billion sessions. Notably, 83% of global AI usage and 75% in the U.S. occurred via mobile apps. ChatGPT held 89% of global AI sessions and 86% in the U.S. When focusing on “search-like” prompts (about 52% of total, categorized as “Asking”), AI reached 28% of global search volume and 17% in the U.S.
“Monthly sessions of AI are now 56% the size of search worldwide and 34% in the US, 4x-5x larger than previous reports that only include web data.”
Ethan Smith stated in the Graphite.io report.
Total search activity, combining engines and AI, grew 26% globally and 16% in the U.S. from 2024 to 2025, with no decline in traditional search.
Coverage and Marketing Implications
Search Engine Land reported the findings on March 9, quoting Smith: “The growth of AI is incremental to search. The pie is getting much bigger.” The article emphasized the need for both SEO and AI optimization (GEO).
Ignite Visibility’s weekly digital marketing news (March 7-13, 2026) stated AI assistants now dominate 56% of global search volume, up significantly and impacting SEO and digital marketing worldwide. It noted platforms like ChatGPT generating 45 billion monthly sessions (83% mobile) and signaled a shift for marketers to optimize for AI-driven search.
ChatGPT Advertising Trends
Retail and grocery brands led ChatGPT ads at 44% in early March 2026, per Sensor Tower data analyzed in two weeks of activity, according to Marketing Dive (March 6). Top brands included Best Buy, Target and Chewy. Other categories: media/education (12.6%), software/tech (11.9%), travel/entertainment (10.4%) and delivery (9.1%).
Social Media Buzz
On March 13, Smith shared the study on X: “I originally hypothesized that AI was over hyped… However, what I found is that the size and trajectory of AI are understated and that AI is much bigger than I thought.” View post. Another post linked the Search Engine Land article, reiterating AI assistants now dominate 56% of global search volume. View post.
The Graphite study excluded non-search surfaces like Amazon and focused on top search engines (Google, Bing, etc.). AI assistants now dominate 56% of global search volume underscores expanding digital discovery, prompting marketers to adapt strategies beyond traditional engines.