I haven’t had time to play with Chatfuel myself, but I found the example that My Electronics Lab had realized with Chatfuel interesting enough for a blog post. Chatfuel is a (free) online service that makes it relatively easy to build a Facebook chatbot. That chatbot recognizes the texts that a use enters and then responds to them. That doesn’t just have to be with text. In the example above, the chatbot sends GET commands to a (other free) online MQTT server. An ESP8266 that connects to that server then responds to that and turns off an LED light on or off again. That LED can be different. Conversely, you can also imagine requesting information from sensors in this way.
Related topic : How to properly reference your blog?
See also : How to set up a Facebook chatbot