The classic historic early chatbots are ELIZA (1966) and PARRY (1972).[5] 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).[6]

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).
I've come across this challenge many times, which has made me very focused on adopting new channels that have potential at an early stage to reap the rewards. Just take video ads within Facebook as an example. We're currently at a point where video ads are reaching their peak; cost is still relatively low and engagement is high, but, like with most ad platforms, increased competition will drive up those prices and make it less and less viable for smaller companies (and larger ones) to invest in it.

Tay was built to learn the way millennials converse on Twitter, with the aim of being able to hold a conversation on the platform. In Microsoft’s words: “Tay has been built by mining relevant public data and by using AI and editorial developed by a staff including improvisational comedians. Public data that’s been anonymised is Tay’s primary data source. That data has been modelled, cleaned and filtered by the team developing Tay.”
We need to know the specific intents in the request (we will call them as entities), for eg — the answers to the questions like when?, where?, how many? etc., that correspond to extracting the information from the user request about datetime, location, number respectively. Here datetime, location, number are the entities. Quoting the above weather example, the entities can be ‘datetime’ (user provided information) and location(note — location need not be an explicit input provided by the user and will be determined from the user location as default, if nothing is specified).

Respect the conversational UI. The full interaction should take place natively within the app. The goal is to recognize the user's intent and provide the right content with minimum user input. Every question asked should bring the user closer to the answer they want. If you need so much information that you're playing a game of 20 Questions, then switch to a form and deliver the content another way.
Simple chatbots, or bots, are easy to build. In fact, many coders have automated bot-building processes and templates. The majority of these processes follow simple code formulas that the designer plans, and the bots provide the responses coded into it—and only those responses. Simplistic bots (built in five minutes or less) typically respond to one or two very specific commands.
ELIZA's key method of operation (copied by chatbot designers ever since) involves the recognition of clue words or phrases in the input, and the output of corresponding pre-prepared or pre-programmed responses that can move the conversation forward in an apparently meaningful way (e.g. by responding to any input that contains the word 'MOTHER' with 'TELL ME MORE ABOUT YOUR FAMILY').[9] Thus an illusion of understanding is generated, even though the processing involved has been merely superficial. ELIZA showed that such an illusion is surprisingly easy to generate, because human judges are so ready to give the benefit of the doubt when conversational responses are capable of being interpreted as "intelligent".