No one really knows how many “things” there are deployed today that have IoT characteristics. IDC’s 2013 estimate was about 9.1 billion, growing to about 28 billion by 2020 and over 50 billion by 2025. You can get pretty much any other number you want, but all the estimates are very large. So what are all these IoT things doing and why are they there? Here’s our attempt to map out the IoT landscape (click to enlarge). As you can see, there are a whole lot of possible organizational approaches to the constituent parts of IoT.