What is an IoT system? A 3-point checklist

Reading the large amount of news on connected technologies, I often wonder what the writer actually means by IoT. I do not want to open the Pandora vase holding the discussion on the definition of IoT; there is already a huge corpus for this and any reader animated by a scientific approach — even a slight one — should look into it and find the definition that suits him best. It is actually interesting that while I was writing this piece, on the IoT Agenda site there is yet another definition. As in the standards world, where too many standards mean no standard, here too many definitions are heading toward no definition. I have the feeling, though, that there is a strong interest in leaving a certain amount of fuzziness on the topic. As it’s possible to play on the vagueness of the concept, everything that has a sensor can be labeled “IoT.” I’ve heard of standard HVAC systems that suddenly became IoT; even better, a switch and a lightbulb are now IoT as they are connected.