In Area51, while I was browsing, I saw 'Internet of Things' and joined this community. The description was:
Beta Q&A site for everyday objects embedded with electronics to be sensed, monitored, and controlled remotely.
But I can't understand the subject to be discussed here. (I want to know)
My approach is more 'enterprise' focused.
Traditionally, industries (auto, banking, oil and gas, manufacturing, retail, etc.) haven't had the insights on equipment operation data beyond 'best practices', 'experience' and so on. With IoT, the aim is to remove some of the guesswork and take more informed decision.
Let me take an example. Traditionally, vehicle maintenance (say, your car) used to be done at a frequency determined by "n miles or n months or whichever is earlier" rule. What never got captured was, exactly how the vehicle was used in that interval (n miles or months). Was the vehicle used abusively? Or, did the driver maintain the optimal speed?
With access to Engine Control Unit (ECU) data, it is now possible to collect driving data and analyze to arrive at the optimal maintenance plan. In fact, it could help drive better insurance plans so that, a better driver pays lesser premium, etc.
The Internet of Things (IoT) is the interconnection of heterogeneous objects through the Internet. This concept was created by Kevin Ashton.
Then, in this community, we talk and solve questions about how to interconnect different objects through the Internet.
These objects are heterogeneous because they can be microcontrollers like an Arduino, a microcomputer like a Raspberry Pi, different sensors, actuators, smartphones, cars, and so on. Anything that you have in your mind. Besides, these objects are ubiquitous because they can be in anywhere: in your home, in movement in the highway, in the sea, crossing the sky, etc. The only thing that these objects need is a connection to the Internet to have the possibility to send messages to other objects. Furthermore, these objects can be intelligent, also called Smart Objects, or not, like sensors and actuators. You can read more about the Smart Objects, Sensors, and Actuators here.
Then, in this community, you can find and ask about how to connect these objects, the problems that you have installing or configuring these objects, or other doubts that you could have about it.
Here you can read a very good survey that talks about the IoT is.
As an addition to CGG's great answer for what IoT is, let me show you the sort of thing we answer here, at Internet of Things.SE:
Questions about home automation are generally welcome here, so anything from smart speakers to fridges, thermostats and locks is allowed.
We also accept a lot of questions about the protocols, hardware and systems that you need for the Internet of Things, both in home settings and industrial uses (e.g. Industry 4.0).
Internet of Things Stack Exchange is also the site for questions about connecting networked devices together effectively, such as making your Amazon Echo device turn the lights on and off just by voice.
So, if your question is about...
... you're in the right place!
If you're looking for support with more traditional devices, such as computers, laptops and tablets, consider asking at Super User instead.
Internet of Things is not a specific technology, or dependant on any specific technology. Rather it is a stage in the evolution of connected devices, enabled by the availability of two things: cheap endpoint compute, and cheap ubiquitous connectivity. We have progressed from telegram, telegraph and POTS, through an era of expensive home and business computers, to a time when it costs only a few $ to enable any device to communicate with other devices.
As well as accessible connectivity, IoT exists in part because of cloud computing, and the ability to extract value from the large amounts of data which can now be collected very cheaply. A good example of this is collecting traffic data flow (by monitoring Sat-Nav activity on cellphones) and mass-transport route and pinch-point data (by monitoring cellphone MAC addresses as they traverse a physical space).
