ChatGPT, the AI chatbot developed by OpenAI, has reached 400 million active users as of February 2025, doubling its user base in less than six months. This growth was highlighted in a report by Andreessen Horowitz, which attributes the surge to advanced features such as multimodal capabilities, real-time voice interaction, and improved reasoning models. Of the 400 million users, 175 million are mobile users, reflecting consistent growth in mobile adoption. The chatbot has also climbed to the fifth most visited website on desktop globally and seventh when combining desktop and mobile traffic. ChatGPT now contributes to 4.8% of new signups for platforms like Vercel, showcasing its growing influence in driving user engagement. Meanwhile, DeepSeek, a Chinese AI tool launched in January 2025, initially captured 15% of ChatGPT's mobile user base and peaked at the second position in global rankings. However, it has since experienced a sharp decline, falling to the 90th position in rankings.