U.S. Secretary of State Hillary Clinton's strong admonition of China this week for its perceived attempts to clamp down on free expression of ideas on the Internet has deepened the differences between the world's top two economies.

China's Foreign Ministry spokesman Ma Zhaoxu blasted the U.S. on Tuesday for what he said was Washington's attempt to meddle in his country's internal affairs in the name of Internet freedom.

Clinton had said in her speech that countries like China, Syria, Cuba, Vietnam and Myanmar resort to restriction of online speech and that repression will fail as a strategy. She also said the US government will earmark an additional $25 million to support digital dissidents fighting online repression.

Chinese authorities have blocked Twitter and are constantly censoring and monitoring microblogging sites and social networks. China had also blocked searches on Egypt and Tunisia as massive popular protests took shape in those countries, fearing a domino effect.

In China's closed system of administration, free speech and unbridled circulation of ideas can easily cause trouble. The ruling Communist party sensed the potential dangers of Internet freedom long back and crafted measures to prevent the Internet from escalating simmering discontent.

Below are some measures China has taken to clip the wings of the biggest potential enemies of the Communist Party -- the Internet and modern communication technologies:

Secret Pro-government Campaign

In 2005, Britain's Guardian newspaper reported that China recruited armies of secret web commentators and put in place sophisticated new monitoring software to lead the war on free Internet. The regime also ordered bloggers and bulletin board operators to register with the government lest they be closed down.

There was a plan to recruit reliable political pacifiers well versed in Marxist theories, the workings of the Chinese government and the internet technology. Their role was to influence media in such a way that the government machinery had the upper hand in swaying popular opinion. The government wanted to seize the high point of internet opinion, a propaganda officer was reported as telling the Southern Weekend newspaper.

A job posting said the applicants for the role had to be proactive in developing discussion, increase control, accentuate the good, avoid the bad, and use internet debate to our advantage.

Internet Police Force

This sophisticated attempt to grab control over the Internet and thereby influence the fastest medium of communication was to augment the efforts of the 30,000-strong Internet police force. The forces had their hands full as they had to constantly keep watch over critical comments popping up in bulletin boards and online discussion forums and delete them within minutes, if not seconds.

When the ordinary Chinese, frustrated with the corrupt machinery, raised their voice against graft and other ills, these were deleted immediately. Even comments critical of the official response to natural disasters were assiduously deleted.

Great Firewall of China

China's formidable censorship machinery, known as the “Great Firewall of China,” has always tried to monitor how the global Internet interacts with the 'Chinese Internet'. This is how global internet giant Google came in the cross hairs with the Chinese administration last year.

The regime's fearsome network of public security organs help the party’s propaganda department and the Ministry of Information Industry in deciding what content should be spiked or covered up on the media, including the Internet.

Physical access to the Internet is provided by nine state-licensed Internet Access Providers (IAP), each of which has at least one connection to a foreign Internet backbone, and it is through these connections that Chinese Internet users access Internet websites hosted outside of China.3 The individual Chinese Internet user buys Internet access from one of several thousand Internet Service Providers (ISPs), who are in effect retail sellers of Internet access that is in turn purchased wholesale from the nine IAPs, according to a report by the Human Rights Watch (HRW) in 2006.

Targeting Internet Content Providers

Besides preventing ISPs from hosting politically objectionable content by holding them liable for doing so, the government also targets the Internet Content Providers (ICPs) which are required to register for and display a license in order to operate legally, and are held liable for all content appearing on their websites, HRW points out.

Organizations including Chinese companies, universities, and government offices have to sign a voluntary pledge not to publish politically objectionable content through automated means and to police content being uploaded by users for unacceptable material.

Search engines likewise maintain lists of thousands of words, phrases and web addresses to be filtered out of search results so that links to politically objectionable websites do not even appear on the search engine’s results pages, even when those websites may be blocked at the backbone or ISP level. Thus, the user is prevented from knowing that the forbidden content exists at all. This is a deliberate choice made by the operator of the search engine, according to the HRW.

Email, Chat Surveillance

Mobile and Internet chat services are required to filter politically sensitive content and if you are a Chinese you will not be surprised when some message that you type and send doesn’t reach the intended recipient.

Complex Regulations

China's Internet is perhaps the most over-regulated system in the world. At least twelve different government bureaus have some authority over the Internet, including the powerful State Council Information Office, the Ministry of Public Security, and the Ministry of Information Industry, says HRW.

News Portals' Role Is To 'Serve Socialism'

The 'Provisions on News Information Services', which was issued in 2005, states that the purpose of news websites is not to inform the public of the facts, but instead to “serve socialism” and to “safeguard the nation’s interests and the public interest.”

In general, news information websites must be part of the official media system, and must register with the government in order to begin operation. This and various other draconian restrictions on news websites flagrantly defy international norms.

Article 19 of the International Covenant on Civil and Political Rights (ICCPR) says: Everyone shall have the right to freedom of expression; this right shall include freedom to seek, receive and impart information and ideas of all kinds, regardless of frontiers, either orally, in writing or in print, in the form of art, or through any other media of his choice.