The sensors and actuators of the IoT tend to be small-scale: temperature, light, etc.
The key factor is the merging of real and virtual, the bringing of Things into the Internet, and allowing communication in both directions between real and virtual and virtual back to real.
On a slightly bigger scale, in the Object Network people are first class and bring their own more complex sensors - for gestures, location, orientation, etc. - and actuators - like screens, glasses, vibration and speakers.
Now the whole thing begins to fill our 3D space - as the Object Network's ability to view the IoT in Augmented Reality indicates.
The 3D IoT
Taking this concept of a 3D IoT to its conclusion:
3D IoT sensors can include full 3D sensor devices that suck in the shape of the world, and sensors like those on the Wii for picking up the motion of your hands and feet, or the Leap Motion that can pick up hand gestures.
3D IoT actuators can include bigger, wall-sized screens, holographic displays, 3D solid displays and 3D printers.
All these technologies enable what were once futuristic applications - instead of bending over a tablet and stabbing at a tiny screen, we'll be standing up, and moving our whole bodies around, interacting with surround-vision displays and holographic objects.
Imagine sculpting a virtual object with your hands, then printing it out. That is a true blend of real and virtual - the "lights and thermostats" Internet of Things will seem rather lame in comparison.
Of course, the ultimate sensor/actuator combo is the robot - a device that can exist in both real and virtual domains simultaneously - it could have a 3D virtual representation showing more about its state and rules, which could be as interactive as the physical robot.
Telepresence robots are a variant of this, merging a real person into a virtual person and back into a nearly-real person again.
The benefit of the Object Network approach to the IoT is that it starts off seeing your world in 3D, so all this is native to its way of working and interacting.