I'm aiming to keep it short and open:
"Internet of Things is a Q&A site concerning the everyday objects that
use networks."
The word "everyday" tries to qualify the objects just a little bit, to exclude phones, computers, and networking equipment. (Perhaps "ordinary objects" would be clearer, but it sounded too alliterative to me.) I thought about qualifying it further like "everyday objects that contain a computer but are not primarily computing devices" but that takes all the punch out of it.
It doesn't describe the objects as containing electronics, computers, or chips (which would be redundant); it doesn't describe the environment the objects are in (IoT objects could be installed in a data center but that doesn't make them servers); it doesn't describe the users of the objects (they aren't limited to "ordinary people" or "non-technical users"); and it doesn't describe the size of the object (pedometers and refrigerators are all welcome in the IoT.)
It doesn't qualify the what the object does with the network. For this definition it doesn't matter if the object uses it for status reporting or permits remote control, or if the object provides remote control or monitors status.
It also doesn't qualify the type of the network; not wired or wireless, digital or analog. It presumes that if an object can get to a network (any network), the implication is that network can ultimately bridge those messages to and/or from the internet.