By Maggie Shiels
Technology reporter, BBC News, Silicon Valley
Google was accused of censoring 2% of search results in China
Microsoft, Google and Yahoo have signed a global code of conduct promising to offer better protection for online free speech and against official intrusion.
The Global Network Initiative follows criticism that companies were assisting governments in countries like China to censor the Internet.
The guidelines seek to limit what data should be shared with authorities, in cases where free speech is an issue.
"This is an important first step," said Mike Posner of Human Rights First.
He told the BBC "What this is is a recognition by all these tech companies, the human rights groups and social investors that there has to be a collective response to this growing problem.
"Companies need to step up to the plate and be more aggressive in challenging unwarranted government interference," he said.
The initiative states that privacy is "a human right and guarantor of human dignity," and the agreement commits the companies to try to resist overly broad demands for restrictions on freedom of speech and the privacy of users.
They will also assess the human rights climate in a country before concluding business deals and make sure their employees and partners follow suit.
"These principles are not going to be a silver bullet, but the most important point for me is to provide transparency," said Danny O'Brien of the Electronic Frontier Foundation.
"We have joined this initiative because we know that a wide range of groups working together can achieve much more than the company acting alone," said Andrew McLaughlin, Google's director of global public policy.
The impetus for such an agreement follows years of criticism that a number of businesses, including Google, Yahoo and Microsoft have complicity built what has been dubbed the "Great Firewall of China".
Skype say they are abiding by Chinese laws over internet use
Google has been accused of complying with Chinese government demands to filter internet searches to eliminate query results regarding topics such as democracy or Tiananmen Square.
Microsoft has come under attack for blocking the blog of a prominent Chinese Media researcher who posted articles critical of a management purge at the Beijing News Daily.
Canadian researchers uncovered that a Skype joint venture in China monitored users' communications.
And a Chinese reporter Shi Tao was jailed for 10 years after Yahoo China provided his personal information to the Chinese government.
Today Yahoo co-founder and CEO Jerry Yang welcomed the new code of conduct.
"These principles provide a valuable roadmap for companies like Yahoo operating in markets where freedom of expression and privacy are unfairly restricted.
Shi Tao's jailing sparked a controversy of Yahoo business practices in China
"Yahoo was founded on the belief that promoting access to information can enrich people's lives and the principles we unveiled today reflect our determination that our actions match our values around the world," said Mr Yang.
While China has been painted as the worst abuser, Colin Maclay of the Berkman Centre for Internet and Society at Harvard University said there are other countries and governments all over the world at fault.
"The number of states actively seeking to censor online content and access personal information is growing.
"And the means employed - technical, social, legal, political - are increasingly sophisticated, often placing internet and telecommunications companies in difficult positions."
The Global Network Initiative was drawn up by the internet companies along with human rights groups, academics and investors.
Adam Kanzer who is the managing director and general counsel at Domini Social Investments said as well as being the right thing to do, it also makes good business sense.
He told BBC News "When you see the industry being caught up in the tactics of various regimes around the world, the business case is very clear. Freedom of expression and privacy is core to their business.
"They depend on a wide open, freely accessible and secure internet. That's what they are about. If people don't trust the internet and believe they are secure, then that is counterproductive to their business."
The plan has yet to receive the support of internet companies in China
The effort is already being seen by some as not going far enough.
"After two years of effort, they have ended up with so little," said Morton Sklar executive director for the World Organisation for Human Rights USA.
"It is very little more than a broad statement of support for a general principle without any concrete backup mechanism to ensure that the guidelines will be followed."
Mr Posner of Human Rights First disputes that and said this agreement has not been set up as a "gotcha system" but as a way "to work with companies to get them to improve what they are doing, credit them when they do it and call them out if they fail."
While it is hoped many more companies will sign up, two European telecommunications firms, France Telecom and Vodafone, are already said to be considering adding their names.