ChatGPT is an AI chatbot developed by OpenAI based on GPT-3.5. It uses neural networks and unsupervised learning to conduct natural conversations. Users can access ChatGPT through its website to ask questions and receive responses. Some advantages are that it provides quick, accurate responses that mimic human conversation across a wide range of topics. However, it is limited by the data it was trained on and does not have perfect knowledge. Overall, ChatGPT demonstrates significant progress in conversational AI capabilities.