This paper looks at the fast growth and incorporation of chatbots in different fields such as marketing, health, education, entertainment, and cultural tourism. In the first step, we outline the history of chatbots, with a focus on the global interest in those applications, which are growing to be highly useful and valuable. The role of social expectations in the contextualization of the chatbot by specifying the design of the interface and the features of interaction is also investigated. To continue, we provide a brief overview of some of the technological concepts and then classify chatbots according to the type of function they are designed for as well as their knowledge domain. This classification gives an understanding of how various chatbots meet the various needs of the users. We also explain the generalized structure of the current generation of chatbots and discuss the well-known development environments used in their construction. Using cases, our study points to the positive future trends of chatbots, implying that with advancements in technology, chatbots will yield greater value and contribute to the improvement of usability throughout industries. We therefore urge research communities to devote more effort in further investigating this emerging technology to its optimal potential.