OpenAI reports 1.2B weekly ChatGPT users, launches GPT-6.1 Sol

OpenAI announced at DevDay that ChatGPT now has over 1.2 billion weekly users, up from 1 billion in July, and 2.5 million business clients. The company also launched GPT-6.1 Sol, a mid-tier model positioned as nearly as powerful as its flagship at lower cost. This signals continued rapid adoption and monetization of AI, reinforcing OpenAI's market leadership and competitive pressure in the AI sector.