Nobody at OpenAI probably expected the comparison to sound this absurd. Instagram needed two and a half months to get a million users. TikTok, roughly five months. Platforms frequented by players searching for an online casino ireland option or placing a quick sports bet went through their own mobile engagement spike around the same time, part of the same rapid app adoption wave. ChatGPT did it in five days, then kept accelerating until Sam Altman walked onto the Dev Day stage in October 2025 and dropped the figure that made every product manager in tech quietly reconsider their KPIs. Eight hundred million weekly. The adoption curve that AI and mobile platforms keep bending in gaming ran almost exactly in step.
Growth That Broke the Adoption Playbook
A Deloitte report tried to give this context by going way back. Half a century for telephones to find 50 million people. Seven years for the internet. Those benchmarks already felt comically slow before ChatGPT doubled from 400 million to 800 million weekly users in under eight months during 2025.
| What happened | When / How much |
| First million users | 5 days after launch (Nov 2022) |
| 100 million monthly active | Two months in (Jan 2023) |
| Crossed 400M weekly | Feb 2025 |
| Doubled to 800M weekly | Oct 2025 |
| Hit 900M weekly | Feb 2026 |
| Queries per day | North of 1 billion |
| Fortune 100 companies using it | 92% |
GPT-5, image generation, Deep Research, a shopping tool in April, group chats by November. Each update dragged in a crowd that had ignored the previous version. And the user base stopped skewing male somewhere around mid-2025, with OpenAI’s own study showing near-parity after an initial 80/20 masculine name split.
Where the Betting Sector Noticed
You don’t get to ten percent of the world’s adult population using one tool without other industries scrambling to copy the interface. Sportsbook operators were early movers. Casino groups and betting platforms bolted ChatGPT-style chatbots onto customer support and live play screens throughout 2025, because once hundreds of millions of people get comfortable typing a question and receiving a conversational reply, making them click through dropdown menus for anything feels like a punishment. VIP betting assistants with voice capability showed up at expos, running on OpenAI’s API or whichever rival model the vendor happened to license that quarter.
What Happened Inside Companies
OpenAI quietly amassed over a million paying business customers by late 2025. Structured use of features like Projects and Custom GPTs spiked 19x in a single year, which tells you people moved past “let me ask it a fun question” and into repeatable daily workflows. Workers on average said they were saving around an hour per day. The heavy users, ten-plus hours a week reportedly, were non-technical employees writing code, which is a sentence that would have gotten you laughed out of a boardroom in 2021.
Revenue went from $3.7 billion to a $10 billion annual run rate by mid-2025. That kind of jump happens when the tool stops being optional for procurement teams, legal departments, and sales orgs that watched their competitors adopt it first.
The Next Hundred Million
By February 2026 another hundred million weekly users had piled in, hitting 900 million, and OpenAI took the occasion to close a $110 billion round at a $730 billion valuation. Nine million paying business accounts. General research remains the top use case at about 36% of all queries, according to First Page Sage’s March 2026 analysis. Most people still use it the way you’d use a search engine, except one that answers in paragraphs instead of links. Sixth most-visited site on earth. Claude and Gemini and Meta AI all carved out their corners, but 5.7 billion monthly visits and 18 billion weekly messages belong to a single product, and the distance between first place and second keeps stretching.
