We have Alexa and Siri, the most famous, but also Replika, Sunny, Juliet, Amelia, Andy and many others.  These are chatbots, systems based on artificial intelligence that are able to talk with users, usually to answer relatively simple and standardized questions. And then there is ChatGPT, which unlike other bots is able to write elaborate texts with a degree of consistency and complexity never before achieved by a machine. But let's take a step back and try to understand how these systems work and how they might develop, along with Luca Trevisan, Professor of Computer Science at Bocconi.