Chatbots have come a long way since then. They are built on AI technologies, including deep learning, natural language processing and  machine learning algorithms, and require massive amounts of data. The more an end user interacts with the bot, the better voice recognition becomes at predicting what the appropriate response is when communicating with an end user.
When one dialog invokes another, the Bot Builder adds the new dialog to the top of the dialog stack. The dialog that is on top of the stack is in control of the conversation. Every new message sent by the user will be subject to processing by that dialog until it either closes or redirects to another dialog. When a dialog closes, it's removed from the stack, and the previous dialog in the stack assumes control of the conversation.
At this year’s I/O, Google announced its own Facebook Messenger competitor called Allo. Apart from some neat features around privacy and self-expression, the really interesting part of Allo is @google, the app’s AI digital assistant. Google’s assistant is interesting because the company has about a decades-long head start in machine learning applied to search, so its likely that Allo’s chatbot will be very useful. In fact, you could see Allo becoming the primary interface for interacting with Google search over time. This interaction model would more closely resemble Larry Page’s long-term vision for search, which goes far beyond the clumsy search query + results page model of today:
Malicious chatbots are frequently used to fill chat rooms with spam and advertisements, by mimicking human behaviour and conversations or to entice people into revealing personal information, such as bank account numbers. They are commonly found on Yahoo! Messenger, Windows Live Messenger, AOL Instant Messenger and other instant messaging protocols. There has also been a published report of a chatbot used in a fake personal ad on a dating service's website.[44]
The bot itself is only part of a larger system that provides it with the latest data and ensures its proper operation. All of these other Azure resources — data orchestration services such as Data Factory, storage services such as Cosmos DB, and so forth — must be deployed. Azure Resource Manager provides a consistent management layer that you can access through the Azure portal, PowerShell, or the Azure CLI. For speed and consistency, it's best to automate your deployment using one of these approaches.
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".