The document discusses various techniques used to design chatbots. It presents a survey of chatbot design techniques from nine research papers and compares the main methods used. The document categorizes chatbots into four types - goal-based, knowledge-based, service-based, and response-based. It also describes existing chatbots like Elizabeth bot, Microsoft LUIS, and Alicebot and discusses their approaches to natural language processing and response generation. The document aims to help researchers identify gaps for future chatbot development.