How: this is a relatively simple flow to manage, and it could be one part of a much larger bot if you prefer. All you'll need to do is set up the initial flow within Chatfuel to ask the user if they'd like to subscribe to receive content, and if so, how frequently they would like to be updated. Then you can store their answer as a variable that you use for automation.
If the success of WeChat in China is any sign, these utility bots are the future. Without ever leaving the messaging app, users can hail a taxi, video chat a friend, order food at a restaurant, and book their next vacation. In fact, WeChat has become so ingrained in society that a business would be considered obsolete without an integration. People who divide their time between China and the West complain that leaving this world behind is akin to stepping back in time.
Ultimately, only time will tell how effective the likes of Facebook Messenger will become in the long term. As more and more companies look to use chatbots within the platform, the greater the frequency of messages that individual users will receive. This could result in Facebook (and other messaging platforms) placing stricter restrictions on usage, but until then I'd recommend testing as much as possible.
[In] artificial intelligence ... machines are made to behave in wondrous ways, often sufficient to dazzle even the most experienced observer. But once a particular program is unmasked, once its inner workings are explained ... its magic crumbles away; it stands revealed as a mere collection of procedures ... The observer says to himself "I could have written that". With that thought he moves the program in question from the shelf marked "intelligent", to that reserved for curios ... The object of this paper is to cause just such a re-evaluation of the program about to be "explained". Few programs ever needed it more.
The term "ChatterBot" was originally coined by Michael Mauldin (creator of the first Verbot, Julia) in 1994 to describe these conversational programs. Today, most chatbots are either accessed via virtual assistants such as Google Assistant and Amazon Alexa, via messaging apps such as Facebook Messenger or WeChat, or via individual organizations' apps and websites.[2] [3] Chatbots can be classified into usage categories such as conversational commerce (e-commerce via chat), analytics, communication, customer support, design, developer tools, education, entertainment, finance, food, games, health, HR, marketing, news, personal, productivity, shopping, social, sports, travel and utilities.[4]
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.
It won’t be an easy march though once we get to the nitty-gritty details. For example, I heard through the grapevine that when Starbucks looked at the voice data they collected from customer orders, they found that there are a few millions unique ways to order. (For those in the field, I’m talking about unique user utterances.) This is to be expected given the wild combinations of latte vs mocha, dairy vs soy, grande vs trenta, extra-hot vs iced, room vs no-room, for here vs to-go, snack variety, spoken accent diversity, etc. The AI practitioner will soon curse all these dimensions before taking a deep learning breath and getting to work. I feel though that given practically unlimited data, deep learning is now good enough to overcome this problem, and it is only a matter of couple of years until we see these TODA solutions deployed. One technique to watch is Generative Adversarial Nets (GAN). Roughly speaking, GAN engages itself in an iterative game of counterfeiting real stuffs, getting caught by the police neural network, improving counterfeiting skill, and rinse-and-repeating until it can pass as your Starbucks’ order-taking person, given enough data and iterations.
Dialogflow is a very robust platform for developing chatbots. One of the strongest reasons of using Dialogflow is its powerful Natural Language Understanding (NLU). You can build highly interactive chatbot as NLP of Dialogflow excels in intent classification and entity detection. It also offers integration with many chat platforms like Google Assistant, Facebook Messenger, Telegram,… 

A chatbot is an artificial intelligence (AI) program that simulates interactive human conversation by using key pre-calculated user phrases and auditory or text-based signals. Chatbots are frequently used for basic customer service and marketing systems that frequent social networking hubs and instant messaging (IM) clients. They are also often included in operating systems as intelligent virtual assistants.

Haptik is one of the world's largest Conversational AI platforms reaching over 30 million devices monthly. The company has been at the forefront of the paradigm shift from apps to chatbots, having built a robust set of technology and tools that enable any type of conversational application. Our platform processed over a billion interactions to date and helps enterprises leverage the power of AI to automate critical business processes like Concierge, Customer Support, Lead Generation and E-commerce.

How: instead of asking someone to fill out a form on your website to be contacted by your sales team, you direct them straight into Messenger, where you can ask them some of their contact details and any qualification questions (for example, "How many employees does your company have?"). Depending on what they respond with you could ask if they'd like to arrange a meeting with a salesperson right there and then.

One pertinent field of AI research is natural language processing. Usually, weak AI fields employ specialized software or programming languages created specifically for the narrow function required. For example, A.L.I.C.E. uses a markup language called AIML, which is specific to its function as a conversational agent, and has since been adopted by various other developers of, so called, Alicebots. Nevertheless, A.L.I.C.E. is still purely based on pattern matching techniques without any reasoning capabilities, the same technique ELIZA was using back in 1966. This is not strong AI, which would require sapience and logical reasoning abilities.