ChatGPT has been No. 1 in app stores for 7 straight months (www.businessinsider.com)

OpenAI’s ChatGPT app has been the most downloaded mobile app across the iOS and Google Play stores for seven consecutive months through September, with Appfigures estimating about 410.8 million downloads year-to-date. That lead dwarfs rivals like Google’s Gemini (131.1M), DeepSeek (79.2M), Grok (46.6M), Perplexity (43.1M) and Meta AI (16.9M). OpenAI CEO Sam Altman reported roughly 800 million weekly active users at DevDay, and research cited by the company put traffic at over 2.5 billion messages per day as of July—about 29,000 messages per second—underscoring the rapid, global uptake (researchers noted that’s more than 10% of the world population). For the AI/ML community, these numbers signal massive, persistent demand for conversational AI and reinforce ChatGPT’s network effects: large user volume accelerates product refinement, data-driven improvements, and ecosystem lock-in (APIs, plugins, integrations). Technically, sustaining hundreds of millions of users and billions of daily messages demands enormous inference and serving infrastructure, sophisticated latency and cost-optimization, ongoing model fine-tuning, and scaled safety/moderation systems. The gap with competitors also intensifies pressure on rivals to innovate on model quality, latency, privacy-preserving data use, and monetization strategies, while raising regulatory and governance considerations around scale and influence.