…utilizing chat, messaging, or other natural language interfaces (i.e. voice) to interact with people, brands, or services and bots that heretofore have had no real place in the bidirectional, asynchronous messaging context. The net result is that you and I will be talking to brands and companies over Facebook Messenger, WhatsApp, Telegram, Slack, and elsewhere before year’s end, and will find it normal.

Derived from “chat robot”, "chatbots" allow for highly engaging, conversational experiences, through voice and text, that can be customized and used on mobile devices, web browsers, and on popular chat platforms such as Facebook Messenger, or Slack. With the advent of deep learning technologies such as text-to-speech, automatic speech recognition, and natural language processing, chatbots that simulate human conversation and dialogue can now be found in call center and customer service workflows, DevOps management, and as personal assistants.
To inspire the next generation of explorers, NASA reaches out to students in schools, community organizations, and public events. A star robotic ambassador is “Rov-E,” a close replica of real NASA Mars rovers. Through Amazon Lex, NASA staff can now easily navigate Rov-E via voice commands -- an effective conversational interface when speaking with large crowds. Multi-turn dialog management capability enables Rov-E "to talk,” answering students’ questions about Mars in an engaging way. Integration with AWS services allows Rov-E to connect and scale with various data sources to retrieve NASA’s Mars exploration information. 
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.
Chatbots are a great way to answer customer questions. According to a case study, Amtrak uses chatbots to answer roughly 5,000,000 questions a year. Not only are the questions answered promptly, but Amtrak saved $1,000,000 in customer service expenses in the year the study was conducted. It also experienced a 25 percent increase in travel bookings.

The most widely used anti-bot technique is the use of CAPTCHA, which is a form of Turing test used to distinguish between a human user and a less-sophisticated AI-powered bot, by the use of graphically-encoded human-readable text. Examples of providers include Recaptcha, and commercial companies such as Minteye, Solve Media, and NuCaptcha. Captchas, however, are not foolproof in preventing bots as they can often be circumvented by computer character recognition, security holes, and even by outsourcing captcha solving to cheap laborers.
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.
Endurance is a companion chatbot that uses neurolinguistics programming (better known as NLP) to have friendly conversations with suspected patients with Alzheimer’s and other forms of dementia. It uses AI technology to maintain a lucid conversation while simultaneously testing the human user’s ability to remember information in different ways. The chatbot encourages the user to talk about their favorite activities, memories, music, etc. This doesn’t just test the person’s memory but actively promotes their ability to recall.
This reference architecture describes how to build an enterprise-grade conversational bot (chatbot) using the Azure Bot Framework. Each bot is different, but there are some common patterns, workflows, and technologies to be aware of. Especially for a bot to serve enterprise workloads, there are many design considerations beyond just the core functionality. This article covers the most essential design aspects, and introduces the tools needed to build a robust, secure, and actively learning bot.
“HubSpot's GrowthBot is an all-in-one chatbot which helps marketers and sales people be more productive by providing access to relevant data and services using a conversational interface. With GrowthBot, marketers can get help creating content, researching competitors, and monitoring their analytics. Through Amazon Lex, we're adding sophisticated natural language processing capabilities that helps GrowthBot provide a more intuitive UI for our users. Amazon Lex lets us take advantage of advanced AI and machine learning without having to code the algorithms ourselves.”
Interface designers have come to appreciate that humans' readiness to interpret computer output as genuinely conversational—even when it is actually based on rather simple pattern-matching—can be exploited for useful purposes. Most people prefer to engage with programs that are human-like, and this gives chatbot-style techniques a potentially useful role in interactive systems that need to elicit information from users, as long as that information is relatively straightforward and falls into predictable categories. Thus, for example, online help systems can usefully employ chatbot techniques to identify the area of help that users require, potentially providing a "friendlier" interface than a more formal search or menu system. This sort of usage holds the prospect of moving chatbot technology from Weizenbaum's "shelf ... reserved for curios" to that marked "genuinely useful computational methods".