A beginner’s guide to online censorshipCensorship seeks to suppress the free exchange of ideas and information deemed unacceptable or threatening by a party in power. The internet has become the world’s largest platform for free speech. Unrestricted access to information empowers individuals like no generation before, giving voices to those who might not otherwise be heard, and sight to those who might not otherwise see.

But censorship threatens the open nature of the internet, inhibiting the world’s free market of ideas. Governments and corporations can silence free speech, limit access to information, and restrict the use of communication tools. Such actions serve the interests of those in power and undermines the civil liberties of everyone else.

For this reason, it is vital for everyone to remain vigilant and act swiftly when threatened by censorship.

Table of contents

  1. Who censors?
    1. Governments
    2. Corporations
    3. Net neutrality
    4. Individuals
  2. What is censored?
    1. Websites and apps
    2. People, events, and organizations
    3. Communication tools
    4. The deep web
  3. How is the web censored?
    1. IP blocking
    2. Keyword filtering
    3. DNS poisoning
    4. Manual enforcement
  4. What types of content should be censored?
  5. How do children factor into the censorship debate?
  6. How can I fight online censorship?
    1. Support free speech advocacy organizations
    2. Know your rights
    3. US court cases
    4. Use encryption and anonymity tools
  7. Which countries censor the most?
  8. Free speech and IP

Who censors?


The most obvious occurrences of censorship are those put in place by law, particularly national governments. Governments of autocratic regimes often censor the web to stifle dissent.

Perhaps the most famous example is China, where the ruling Communist Party has instituted a complex, nationwide censorship system and well-staffed internet police force. Google famously exited the Chinese market because it refused to comply with the government’s censorship requirements for search results.

Hundreds, if not thousands, of websites, social networks, and apps are blocked by a blacklisting system commonly referred to as the Great Firewall. The Great Firewall notably blocks access to western social networks like Facebook and Twitter, news sources, messaging apps, and even Comparitech.

In China’s case, the reason for this type of censorship is two-fold: it suppresses dissent on mediums not under the government’s thumb, and it protects domestic internet companies from international competition. The void that Google left in China gave rise to Baidu, the country’s largest search engine, for example.

The censorship goes further than just blocking content, however. Those who speak out even on domestic public forums can be jailed or worse. Certain key words and phrases cannot be sent to friends or followers on Chinese social media.

Censorship mechanisms put in place by governments often serve as a means of not only preventing discourse, but of identifying and punishing those who engage in what authorities perceive as the wrong discourse.

Whether it be banning a book in schools or jailing a dissident, governments often argue that doing so is in the public interest.

Note that in China and other countries, much of the censorship is actually performed by ISPs and internet companies at the request of the government.


A corporation, such as an ISP or internet company, might censor content at the behest of a government authority. In China, ISPs are responsible for blocking websites, while social media companies are tasked with filtering messages and posts containing sensitive keywords.

Corporations sometimes engage in censorship to hinder competition or otherwise protect their own assets. Deleting negative reviews and comments on their product or service is one example of this. Another is when the brand logos of certain products are blurred out of videos in order to protect advertisers in competition with those brands.

Corporate censorship often refers to a different practice: threatening staff with termination, monetary loss, or access to the marketplace. A company employee who witnesses an ethics violation could get fired if he tells anyone outside of the company, for instance.

Corporations censor content that they think will damage their public image. Rapper Ice-T altered the lyrics of Cop Killer when pressured to do so by Time Warner. An episode of South Park was censored by Comedy Central–a TV channel under the Viacom umbrella–because it depicted the Muslim prophet Muhammed. Youtube routinely scrubs search results of videos that contain pornographic content, abuse, and hate speech.

Net Neutrality

Perhaps the most contentious debate around censorship today is that of net neutrality. Net neutrality argues that the internet should be treated like a utility: all websites and apps receive equal treatment in terms of access. But telecommunication corporations, which have been buying up content creation companies, want to funnel people toward the content that makes them money. To do this, they throttle traffic to competitors such as Netflix, while connections to their own entertainment offerings are unfettered.

This practice was banned under an FCC order in the United States, but reinstated under the Trump administration. When Joe Biden took the presidency in 2021, he signed an Executive Order instructing the FCC to restore net neutrality rules undone during the Trump years. In late 2023, the FCC’s chairwoman Jessica Rosenworcel, stated that the FCC planned to re-introduce net neutrality rules.

Corporations can also censor their own content to protect business interests. To use Netflix as an example again, it does not allow users to view the catalogs of other countries. A Netflix subscriber in the UK cannot watch shows exclusive to subscribers in the United States, for example, unless they use a VPN to spoof their location. This is because Netflix is required by copyright holders to honor content licensing restrictions that apply to individual countries.


Censorship can even take place on an individual level. Social networks like Facebook and Twitter allow users to block content from certain users and sources. Censorship is an issue of individual liberty, so there’s nothing inherently wrong about this when it comes to civil rights. But weeding out opposing views and only seeing self-affirming posts that validate what a person already thinks probably isn’t a healthy practice.

What is censored?

Websites and apps

Autocratic regimes often censor websites that publish opposing views that threaten their power or public image. Notably, social media and news sources are frequent victims of state-sponsored online censorship. In Turkey, major social media sites including Facebook and Twitter were blocked from public view after the president arrested a dozen political opponents.

The Great Firewall has taken this a step further by blocking websites that instruct netizens how to evade censorship. This is the case with Comparitech, which has published tutorials and VPN recommendations for bypassing the Great Firewall. Without a VPN or some other type of proxy, this website cannot be viewed from mainland China.

Tip: You can see what sites are blocked in China here.

Apps can also be blocked or outlawed. WhatsApp has been blocked permanently or temporarily in multiple countries including China, Turkey, and Brazil. Dating apps in ultra-conservative Muslim nations are off the table as well.

People, events, and organizations

Sometimes censorship targets particular people and organizations deemed a threat to those doing the censoring. In China, all websites, text messages, advertisements, and social media posts that even mention the Falun Gong spiritual movement, which authorities persecuted starting in the 1990s, are scrubbed from sight. Similarly, anything relating to the June 4, 1989 Tiananmen Square massacre is heavily censored.

Communication tools

Social media and messaging apps like WhatsApp, Facebook Messenger, and Snapchat pose a threat to autocratic governments because, although correspondence is relatively private, it is more difficult to control. WhatsApp has been blocked permanently in China and temporarily in several other countries including Turkey and Brazil.

Authorities are especially wary of WhatsApp because chats are encrypted, meaning only the intended users can view the contents of their messages. Third parties that try to intercept communications will only see jumbled text due to the encryption.

For this reason, authorities in Brazil argue that WhatsApp could be used in drug deals and terrorist attacks, which justifies temporary service outages. In the UK, the National Crime Agency described Meta’s decision to roll-out end-to-end encryption for Facebook Messenger as “hugely disappointing.”

China’s banishment of western chat apps gave way to the rise of WeChat, the country’s largest chat app made by domestic tech giant Tencent. Tencent cooperates with the government by using sophisticated censorship measures such as keyword filtering–blocking messages or links containing sensitive content like “falun gong.” Temporary and permanent account bans are placed on repeat offenders.

The deep web

Most people find what they are looking for on the internet using Google. But Google and most other popular search engines only index a tiny fraction of the content on the internet. There’s good reason for this; most of the other stuff either can’t be indexed or isn’t useful. It contains old web pages, social media content, private files stored in the cloud, the contents of apps, court records, and academic journals, to name a few.

What’s left is known as the “surface web,” and experts estimate the deep web is about 500 times larger than what can be turned up in search results. Everything else is censored, though not necessarily for the same motives as a state or corporate censorship.

A small sliver of the deep web is known as DarkNet, which contains websites that can only be accessed using Tor. Tor is anonymity software that can be used to access the hidden .onion websites that make up DarkNet–sites that don’t want to be found. They include marketplaces for illicit goods and services, secret blogs, forums, and chat rooms, and private gaming servers.

If you’re interested in uncovering the deep web and DarkNet, see our guide to accessing the deep web and darknet.

How is the web censored?

Many methods of blocking content on the web exist for those with the power to do so. The most common bottleneck where authorities can efficiently censor large swathes of the population is at the ISP level. ISPs, or internet service providers, act as gateways for everyone connected to the internet.

IP blocking

Governments can order ISPs to block the IP addresses and domain names of specific websites and apps. Every device on the internet–be it the one your reading this article on now or a server hosting a web site or app–is assigned a unique IP address. When someone tries to access a web page, a request is sent to the ISP, who resolves the request by finding the corresponding IP address. The ISP then connects the two devices, such as a laptop and a website, so traffic can flow freely between them. ISPs have the power to selectively block such requests and traffic using a firewall.

IP blocking is the presumed method used by Netflix to prevent users from accessing content from outside of their country of residence. Netflix routinely blacklists IP addresses of proxy servers, such as VPNs and smart DNS providers.

Keyword filtering

As mentioned above, keyword filtering identifies and blocks content containing keywords deemed inappropriate by an authority. This takes place on the client, website, and application levels as well as the ISP level.

For example, WeChat will block messages containing sensitive keywords that undermine party rule in China. Search engines can also limit results returned when certain keywords are searched.

ISPs implicit in censorship use deep packet inspection to mine the contents of internet traffic for sensitive keywords. On a small scale, this could be done by routing all traffic through a proxy server which inspects traffic and blocks anything containing blacklisted keywords.

On a country-wide scale, such as in China, this requires a more complex intrusion detection system (IDS). In such a system, copies of packets are created and passed to filtering devices so that the traffic flow isn’t interrupted. If banned content is detected, the ISP sends connection reset requests to the server until the connection is abandoned altogether.

DNS poisoning

DNS poisoning–also known as DNS spoofing, hijacking, and tampering–occurs when corrupt DNS data causes traffic to be diverted to the wrong IP address. The attacker, or in some cases the government and ISP, poison the resolver cache on a nameserver, where web page requests are sent.

In China, the DNS entries for Facebook and other websites were poisoned so that anyone who tried to go to those sites would be redirected to a dead end. Some experts say these requests were sent to other sites that authorities disapproved of, resulting in a distributed denial-of-service (DDoS) attack.

Changing a domain name is not as simple as changing an IP address, so this method can be more effective than IP blocking.

Sometimes DNS hijacking and keyword filtering are implemented in unison. Routers can prevent unwanted communication by hijacking DNS requests containing sensitive keywords and injecting altered DNS replies.

Manual enforcement

When all of the automated methods above fail, there are always good old-fashioned humans able to do the dirty work. China’s internet police is estimated to comprise of a 50,000-strong force. They order the entities hosting sensitive content to remove it or face punishment.

In addition to the internet police, countries like China and Russia pay commentators on social media to support ruling parties and disparage opponents online.

What types of content should be censored?

The First Amendment of the United States does not protect all forms of speech and expression. Obscenity, child pornography, defamation, and speech that incites “imminent and immediate” lawless action (yelling “fire!” in a crowded movie theater when there is none) are a few. Hate speech overlaps with some of these categories as well. Obscene content is defined as something an average person would find objectionable and with no serious literary, artistic, political or scientific value.

How do children factor into the censorship debate?

The responsibility for protecting children from obscene, vulgar, or pornographic content generally lies with parents. That being said, governments have instituted mechanisms like movie and video game rating systems to help parents judge if material is appropriate for their children.

While this is a common practice in modern society, where the line should be drawn between acceptable and not acceptable for children is still debated today.

Under the guise of protecting children, overreaching policies have been challenged all the way to the US Supreme Court, such as in ACLU v. Reno. In that case, the Communications Decency Act was struck down, affirming that online speech deserves the full First Amendment protection.

How can I fight online censorship?

Support free speech advocacy organizations

A handful of great organizations fight for a free and open internet across the world. They raise awareness, educate the public, hold events, lobby legislatures, engage in campaigns, and call out anti-free speech practices. Some of their key issues include net neutrality, freeing imprisoned journalists, advocating for greater government transparency, supporting encryption, and generally keeping the internet free and open.

You can support these organizations by signing up for their newsletters, supporting them on social media, joining campaigns, contacting lawmakers through their websites, and, of course, donating money.

You can find a list of organizations below.

Know your rights and the organizations that fight censorship

In the US, free speech is covered in the First Amendment. But every country is different. Learn about your rights and stay vigilant. If you feel your rights are being infringed upon, here are some organizations that guard whistleblowers, protect free speech, and/or actively fight against censorship:

US court cases

In addition to the First Amendment, dozens of important court cases lay out the bounds of free speech and expression in the US. Here are a few that deal specifically with technology and censorship:

  • American Civil Liberties Union et al. v. Janet Reno
  • CompuServe Incorporated v. Patterson
  • Stratton-Oakmont and Porush v. Prodigy
  • Dial Information v. Thornburgh, 938 F.2d 1535
  • Information Provider’s Coalition v. FCC
  • Miller v. California
  • U.S. v. Thomas

Use encryption and anonymity tools

The best way to evade state-sponsored censorship and spying is to utilize encryption and/or anonymity software. You can do this in a number of ways:

Encryption ensures no one can snoop on your files and communications except for those whom you want to see them. Modern encryption algorithms cannot yet be cracked by brute force.

Encryption and anonymity tools are especially important for whistleblowers. Those who witness violations of free speech should be allowed to speak up without being reprimanded.

Which countries censor the most?

There are a number of indexes that rank countries by their right to free expression. They include the Freedom House Freedom of the Press report, Reporters Without Borders Press Freedom Index, and the Open Net Initiative.

While this article often cites China due to the enormity and sophistication of its censorship system, countries in Africa, the Middle East, and North Korea are often cited as the most heavily censored. Western European countries typically rank the highest for press and internet freedom.

Free Speech and IP

Free speech sometimes conflicts with the principle of intellectual property, in which the creator of material controls how, when and where that material may be used by other parties.

Intellectual property rights are important to protect content creators, but those rights must be balanced so as not to infringe on the best interests of the public. Quoting a politician’s speech in an essay or including excerpts from scientific journals in a report, for example, should not be censored.

In the United States, this sort of speech is protected under Fair Use. Fair Use is a legal guideline that states copyrighted material may be used without the copyright owner’s consent for limited and “transformative” purposes, such as commenting, criticizing, and parody.