Remember though that IoT is not the Raspberry and yes, the Raspberry is a learning toy (and much more) and a REALLY fun one at that.
The definition of IoT is:
"The Internet of Things (IoT) is the network of physical objects—devices, vehicles, buildings and other items—embedded with electronics, software, sensors, and network connectivity that enables these objects to collect and exchange data."
I myself think that the IoT has just started.