Things in IoT refer to devices that have unique identities and can perform remote sensing, actuating, and monitoring capabilities. They can exchange data with other connected devices, applications, or collect data from other devices to process locally or send to centralized servers. The document discusses the key characteristics of big data including volume, variety, and velocity. It also outlines the functional blocks of IoT including application, device, management, security, communication, and services. The purpose of an information model is to define the structure of all information in an IoT system including attributes and relations of virtual entities without describing how information is represented or stored.