Censorship, by definition, is the control of information in a society, achieved by officially examining, modifying, and limiting the publication of movies, books, news reports, blogs, social media and other mediums. It is most often used to suppress any idea or content found to be not suitable by the government. Each country has its own moral code and/or law that limits what can be expressed. Some countries are very tolerant in sexual expressions, religious ideologies, dressing styles and speech, while others are not. Those more intolerant countries would generally have more censorship on information than their counterparts.
Censorship started in Ancient Greece in Athens, where freedom of speech was reserved for those in power. Some poets were banned, and authors of seditious writings were punished. The most famous example is probably that of Socrates, who was convicted for “corrupting the minds of the youth”, planting in them nontraditional ideas. He was forced by the state to commit suicide.
Before the 19th century, censorship was primarily executed by the Roman Catholic Church. It banned books that were deemed heretical and/or anti-clerical (Publishing the Index Librorum Prohibitorum, or List of Banned Books). Famous intellectual figures on the list include John Milton, Galileo Galilei, and Immanuel Kant. The aim was “to protect the faith and morals of the faithful by preventing them from reading heretical and immoral books”. Authors who printed and published their books without approbation were excommunicated from the church.
The most extreme modern example of state-censorship is North Korea. In North Korea, TVs and Radios are only allowed to receive government frequencies, and it is a serious criminal offense to receive signals outside of the country. Journalists are mandated to “guard, defend and advocate” the Workers’ Party’s ideologies and heads. Access to the global Internet is only available to high ranking officials, and only some universities provide strictly monitored computers. North Korea also provides its own internet system, the “Kwangmyong”, which is open to a few citizens. It is filtered by the Korea Computer Centre to ensure only “acceptable” information can be accessed.
Censorship is also prominent in China. There is no access to foreign social media and “the Great Firewall” blocks many foreign sites including Facebook, Youtube, Google, and Twitter. The local social media like Weibo is also heavily censored by the government. Anything sexual/pornographic, “politically sensitive”, “libelous” and conspiracy theory related would be banned and the author could be subject to criminal charge. Searching “politically sensitive” information on China’s own search engines like Baidu would reveal “according to relevant laws and regulations, some search results cannot be displayed”. “Politically sensitive” vocabularies are also banned on social media; some examples include the Tiananmen Square Massacre, “Communist Bandits (how the Kuomintang referred to the Communist Party during the Chinese civil war)”, and Taiwan Independence. Sensitive vocabularies are replaced with asterisks (*) on social forums. Central propaganda agency also orders news agencies, TV Channels and websites to not include a news story/parts of a story due to “political sensitivity”. Chinese news presses in the West reported about a Zhou Yongkang (corrupt senior leader of the Communist Party) half a year before the information was released in China. There was no information until the Communist Party decided to release the news.
Censorship does not only exist in Communist countries. In the western world, censorship is usually implicit. In the U.S., there is constantly subtle manipulation of reality in mass media outlets, and news medias would intentionally not include a story or part(s) of a story because of political pressure from government officials and powerful individuals, economic pressure from advertisers and funders, or legal pressure (threat of lawsuit from deep-pocket individuals, cooperations and institutions). Censorship is not necessarily a bad thing. It can protect citizens from harmful content that can potentially be detrimental to society as a whole (such as child pornography or ISIS propaganda). If the U.S. could censor more content from ISIS, perhaps some of the terror attacks resulted from terrorist propaganda could have been prevented. It really depends on how the state chooses to use it; if used to the extreme, then freedom of speech is no longer present. But if not enough, then the illegal content access can be harmful.