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.

1. AI-based: these ones really rely on training and are fairly complicated to set up. You train the chatbot to understand specific topics and tell your users which topics your chatbot can engage with. AI chatbots require all sorts of fall back and intent training. For example, let’s say you built a doctor chatbot (off the top of my head because I am working on one at the moment), it would have to understand that “i have a headache” and “got a headache” and “my head hurts” are the same intent. The user is free to engage and the chatbot has to pick things up.
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."
However, chatbots are not just limited to answering queries and providing basic knowledge. They can work as an aid to the teacher/instructor by identifying spelling and grammatical mistakes with precision, checking homework, assigning projects, and, more importantly, keeping track of students' progress and achievements. A human can only do so much, whereas a bot has virtually an infinite capacity to store and analyse all data.
Because chatbots are predominantly found on social media messaging platforms, they're able to reach a virtually limitless audience. They can reach a new customer base for your brand by tapping into new demographics, and they can be integrated across multiple messaging applications, thus making you more readily available to help your customers. This, in turn, opens new opportunities for you to increase sales.

One of the most thriving eLearning innovations is the chatbot technology. Chatbots work on the principle of interacting with users in a human-like manner. These intelligent bots are often deployed as virtual assistants. The best example would be Google Allo - an intelligent messaging app packed with Google Assistant that interacts with the user by texting back and replying to queries. This app supports both voice and text queries.

A chatbot (also known as a spy, conversational bot, chatterbot, interactive agent, conversational interface, Conversational AI, talkbot or artificial spy entity) is a computer program or an artificial intelligence which conducts a conversation via auditory or textual methods.[1] Such programs are often designed to convincingly simulate how a human would behave as a conversational partner, thereby passing the Turing test. Chatbots are typically used in dialog systems for various practical purposes including customer service or information acquisition. Some chatbots use sophisticated natural language processing systems, but many simpler ones scan for keywords within the input, then pull a reply with the most matching keywords, or the most similar wording pattern, from a database.