Historical revolution of journalism ethics
1. First stage (16th-17th centuries): Emergence of ethical discourse in Western Europe
2. Second stage (18th century): Press controls weakened, journalists espoused a "public ethic"
3. Third stage (19th century): Evolution of the public ethic into an explicit liberal theory of the press
4. Fourth stage (20th century): Development and criticism of the liberal model
5. Fifth stage (Mixed media): Increasing numbers of non-professional citizen journalists and bloggers engaging in journalism