IT stands for information technology and refers to technologies that are used to store, retrieve, transmit, and manipulate data. The document discusses the role of IT in business across different eras from pre-mechanical to modern electronic age. It outlines several applications of IT in business such as accounting, finance, production, human resource management, and e-commerce. While IT provides advantages like connectivity, cost-effective marketing, and better customer service, it can also enable computer crimes and lack of privacy if abused.