Chatbots – also known as “conversational agents” – are software applications that mimic written or spoken human speech for the purposes of simulating a conversation or interaction with a real person. There are two primary ways chatbots are offered to visitors: via web-based applications or standalone apps. Today, chatbots are used most commonly in the customer service space, assuming roles traditionally performed by living, breathing human beings such as Tier-1 support operatives and customer satisfaction reps.
NBC Politics Bot allowed users to engage with the conversational agent via Facebook to identify breaking news topics that would be of interest to the network’s various audience demographics. After beginning the initial interaction, the bot provided users with customized news results (prioritizing video content, a move that undoubtedly made Facebook happy) based on their preferences.
Rather than having the campaign speak for Einstein, we wanted Einstein to speak for himself, Layne Harris, 360i’s VP, Head of Innovation Technology, said to GeoMarketing. "We decided to pursue a conversational chatbot that would feel natural and speak as Einstein would. This provides a more intimate and immersive experience for users to really connect with him one on one and organically discover more content from the show."
In 1950, Alan Turing's famous article "Computing Machinery and Intelligence" was published, which proposed what is now called the Turing test as a criterion of intelligence. This criterion depends on the ability of a computer program to impersonate a human in a real-time written conversation with a human judge, sufficiently well that the judge is unable to distinguish reliably—on the basis of the conversational content alone—between the program and a real human. The notoriety of Turing's proposed test stimulated great interest in Joseph Weizenbaum's program ELIZA, published in 1966, which seemed to be able to fool users into believing that they were conversing with a real human. However Weizenbaum himself did not claim that ELIZA was genuinely intelligent, and the Introduction to his paper presented it more as a debunking exercise:

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.
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".