Artificial neural networks, invented in the 1940’s, are a way of calculating an output from an input (a classification) using weighted connections (“synapses”) that are calculated from repeated iterations through training data. Each pass through the training data alters the weights such that the neural network produces the output with greater “accuracy” (lower error rate).
Google, the company with perhaps the greatest artificial intelligence chops and the biggest collection of data about you — both of which power effective bots — has been behind here. But it is almost certainly plotting ways to catch up. Google Now, its personal assistant system built within Android, serves many functions of the new wave of bots, but has had hiccups. The company is reportedly working on a chatbot that will live in a mobile messaging product and is experimenting with ways to integrate Now deeper with search.
A chatbot (sometimes referred to as a chatterbot) is programming that simulates the conversation or "chatter" of a human being through text or voice interactions. Chatbot virtual assistants are increasingly being used to handle simple, look-up tasks in both business-to-consumer (B2C) and business-to-business (B2B) environments. The addition of chatbot assistants not only reduces overhead costs by making better use of support staff time, it also allows companies to provide a level of customer service during hours when live agents aren't available.

A chatbot is an artificial intelligence (AI) program that simulates interactive human conversation by using key pre-calculated user phrases and auditory or text-based signals. Chatbots are frequently used for basic customer service and marketing systems that frequent social networking hubs and instant messaging (IM) clients. They are also often included in operating systems as intelligent virtual assistants.

2. Flow-based: these work on user interaction with buttons and text. If you have used Matthew’s chatbot, that is a flow-based chatbot. The chatbot asks a question then offers options in the form of buttons (Matthew’s has a yes/no option). These are more limited, but you get the possibility of really driving down the conversation and making sure your users don’t stray off the path.
The classic historic early chatbots are ELIZA (1966) and PARRY (1972).[10][11][12][13] More recent notable programs include A.L.I.C.E., Jabberwacky and D.U.D.E (Agence Nationale de la Recherche and CNRS 2006). While ELIZA and PARRY were used exclusively to simulate typed conversation, many chatbots now include functional features such as games and web searching abilities. In 1984, a book called The Policeman's Beard is Half Constructed was published, allegedly written by the chatbot Racter (though the program as released would not have been capable of doing so).[14]