Earlier this year net giants Google and Yahoo came under fire from Human Rights Watch and Reporters Sans Frontieres, for their activities in China. But is the criticism warranted?
Google has faced tough criticism of its China policy
In 2003 the Chinese police who had been monitoring message boards, blogs and personal emails, asked for the sign up account details of two anonymous bloggers.
These were handed over by Yahoo China to the Chinese Government.
More than 57 Chinese people have been arrested as result of discussing democracy on the internet, say Amnesty International.
Human Rights Watch, a New York based campaign group, says a line has been crossed.
"Google, Yahoo and Microsoft no longer carry out the censorship for the Chinese government," says Asia Director, Brad Adams, "they are the censor."
This comment stems from the lack of clarity over what is being censored, who has initiated it, and why.
There are two types of censoring at work. Firstly, whole websites are eliminated from Yahoo and Google in China.
De-listed sites are skipped over when the search engine trawls the web for results. Neither Yahoo nor any other company has released a list of websites that have been de-listed for their political and religious content.
As Judy Lin, a former Reuters reporter in Beijing, says: "I found it very difficult to do my job.
"I couldn't access the New York Times, The Washington Times, BBC News or any websites about Tiananmen square."
Additionally, typing in certain words, such as democracy, human rights, and the Chinese opposition group Falungong will produce error pages.
In an official statement, Yahoo said: "It is our understanding that every internet and media company doing business in China receives a list of prohibited words.
"It's important to distinguish that as of October 2005, Ali baba now operates the combined entity including the Yahoo China business.
"We no longer manage day to day operations in China, so we do not have a copy of this list of prohibited words."
That is not true, according to Brad Adams.
"There was talk of a list that the Chinese government drew up and handed to the internet companies. There is no list, and Yahoo in particular is doing the Chinese Government's bidding by predicting which words will be problematic, testing them against the firewall and then implementing them."
Certain results are omitted from Google searches in China
Human Rights Watch has repeatedly asked for copies of this list, and has never been given it.
These firewalls are maintained because the whole of China is served by only nine servers, through which all internet traffic is directed.
In addition, both Reporters Sans Frontiers and Human Rights Watch maintain that Chinese censorship is some of the most elaborate and comprehensive in the world.
Julian Pain from RSF challenges the legal basis for these lists , saying: "These are not actually legal: nowhere in the Chinese constitution does it say that certain words are illegal on internet sites."
Despite this China is viewed by the internet companies as a very lucrative market, with more than 100 million users online at any one time.
Yahoo, Google and other internet firms maintain they are interested in pursuing the utopian ideals on which they were founded.
Yahoo says the internet is a "positive force in China and a growing Chinese middle class is benefiting greatly from more education, communication, and technology".
Judy Lin however, is sceptical, saying: "Of course all the companies are going after this giant market: the internet has become such an important part of Chinese life, with the average college student spending at least six hours a week online"
Brad Adams understands why there is such a furore over this issue because "in the future everything will be done on the internet: shopping, information retrieval and voting".
Chinese journalist Bu Hua, and Media Academic Shou Ming say there are more than 30,000 people involved in maintaining censorship within the Chinese government, monitoring information and discussions on message boards.
However both emphasise that the effects of this censorship are relatively small.
"Chinese citizens are not interested in overthrowing the government, or this Western concept of the public sphere" says Shou, "they want to talk about day to day concerns.
Yahoo says it bans words on an official list from the Chinese government
"Whilst each case is very sad for the people involved, fifty seven people arrested in a country of 1.4 billion is not very much."
Both feel disappointed by the restrictions posed by the Chinese government, but claim that in practice, the firewalls do not have much effect.
Both her and Shou Ming use tactics like breaking up words or underscoring them to find ways around the censors.
Others in China use proxy servers - computers in another country which act as the gateway to the net outside of China.
Critics of internet companies like Google and Yahoo argue that despite the assurances they are still treading too softly. There is talk of an ethical code to be launched soon.
"There is no chance that China will throw out Yahoo, Microsoft or Google" says Brad Adams.
"Dissidents use their sites, which makes them 'honeypots' that the Chinese government can monitor. And the Chinese need the new technology and software these companies bring in, if only to copy it.
"If Google, Yahoo and Microsoft stand together and are divided and ruled by the Chinese, they will be able to uphold an ethical code."