Microsoft has transformed Bing into an AI-driven search engine, integrating OpenAI's GPT-4 into a new feature known as Bing Chat, launched on February 7, 2023. With a million people signing up within the first 48 hours, Bing Chat has sparked significant interest. Currently, this feature is exclusive to Microsoft Edge users and the Bing mobile app.

This AI chatbot feature has drawn attention for producing several intriguing "hallucinations". It has shown itself to be more argumentative than ChatGPT, leading to some humorously contentious situations. Furthermore, it exhibited vulnerabilities to prompt injection attacks, inadvertently revealing hidden prompts, rules, and its internal code-name, "Sydney". Despite these foibles, Bing Chat attracted a staggering 100 million active users by March 2023.

Bing Chat transitioned from a Limited Preview to an Open Preview on May 4, 2023, scrapping the waitlist but maintaining its exclusive accessibility via Microsoft Edge or Bing mobile app, requiring a Microsoft account.

Microsoft has implemented several restrictions to address some issues. Initially, the total number of chat turns (user question and Bing's reply) was limited to 5 per session and 50 per day per user. Also, Microsoft dialed down the model's emotional expressions to prevent its eccentric behavior during extended chat sessions. These limits were later adjusted to 20 turns per session and 200 per day.