The document discusses the evolution of media through four ages:
1) Pre-Industrial Age (before 1700s) - People used tools of stone, bronze and iron, developed paper, and communicated through cave paintings and clay tablets.
2) Industrial Age (1700s-1930s) - Steam power was harnessed, printing press allowed for mass production of books and newspapers, telephone and motion pictures were invented.
3) Electronic Age (1930s-1980s) - Invention of the transistor led to devices like the transistor radio, television, computers and efficient long-distance communication.
4) Information Age (1900s-present) - Internet allowed for social media and digital sharing of voice