The first form of an Internet of Things was a vending machine connected to internet so its status can be known remotely. But we can say that it was between 2008 and 2009 that for the first time the things/people ratio get growing from 0.08 in 2003 to 1.84 in 2010 and the Internet of Things came into existence.
The Internet of Things has many use cases which include: consumer applications, smart home and elder care. It is useful in the fields of medicine and healthcare, transportation, V2X communications (which includes Vehicle to Vehicle, Vehicle to Infrastructure, and Vehicle to Pedestrian), home building, manufacturing, agriculture, maritime, security, laboratory and military. There are two terms special for medical and military IoT, IoMT and IoBT which are the synonyms for "Internet of Medical Things" and "Internet of Battlefield Things" consecutively.