Internet of Things (IoT) is the networking of physical/mechatronics/embedded systems for connecting and exchanging data with other devices and systems over the internet.
IoT is all about the networking and integration into the OSI networking model
Source: https://www.imperva.com/learn/application-security/osi-model/
so based on the OSI model, we can divide IoT into
Web of Things (WoT):
deals with layer 7 of OSI i.e. the existing internet architecture is used for the communication aspects [nodejs servers, SQL/NoSQL databases, HTTP APIs, HTML, CSS web pages, etc]
Internet of Things (IoT):
deals with layers 1-6 of OSI i.e. deals with the creation of our own network system using technologies like BlueTooth, ZigBee, etc
Source: https://webofthings.org/2016/01/23/wot-vs-iot-12/
Approaches for Building IoT Systems
Any IoT application has 4 nodes/components