The idealists who founded some of the most successful technology companies now find themselves entangled in controversy over the vast US government surveillance program denounced as Orwellian.

Ironically, the firms accused of being part of a Big Brother network began with lofty ideals such as Facebook's to make the world "more open and connected" or Google's "to organize the world's information and make it universally accessible and useful."

"By the times the companies are making billions of dollars they are probably not that idealistic anymore," said Roger Kay, an analyst and consultant with Endpoint Technologies Associates who has followed the sector since the early days of the Internet.

"They have had to make decisions to make money rather than protecting the rights of their users," he added.

Joseph Hall, senior technologist at the Washington-based Center for Democracy and Technology, said companies like Google, Facebook and Apple end up collecting vast amounts of data in a quest to "monetize" their large user base, and thus become important targets for law enforcement.

"The move to the cloud is significant," Hall said. "All that data is available because so much processing power and storage is sourced so quickly."

Hall said that as companies mature after public share offerings, "there is a lot of pressure to do things that are different from their idealistic missions. They have to create value for the shareholders."

Under the PRISM program, revealed in the past week, the secretive National Security Agency can issue directives to Internet firms demanding access to emails, online chats, pictures, files, videos and more, uploaded by foreign users.

Some of the biggest tech firms were caught up in the program, including Microsoft, Yahoo!, Google, Facebook, Apple, PalTalk, AOL, Skype and YouTube.

The service providers deny they have given the government backdoor access to customer data, insisting they provide data only when compelled by law.

The polemic in the United States comes at the same time as other nations, including China, use online technology to spy on their citizens, highlighting concerns that the Internet is being subverted by governments.

"Unwarranted government surveillance is an intrusion on basic human rights that threatens the very foundations of a democratic society," Tim Berners-Lee, inventor of the World Wide Web, said in a statement to the Financial Times.

"I call on all Web users to demand better legal protection and due process safeguards for the privacy of their online communications, including their right to be informed when someone requests or stores their data."

Lee and other Internet pioneers have always viewed the Internet as a means to enhance personal freedom. His World Wide Web Foundation is dedicated "to achieving a world in which all people can use the Web to communicate, collaborate and innovate freely, building bridges across the divides that threaten our shared future."

CDT's Hall said that "the epitome of idealism is two people in their garage creating great services," but that when companies grow, "it becomes more complicated."

These firms "come off looking very Big Brother, but to be fair, we don't really know what is going on without getting classified briefings."

He noted, however, that "their continued success depends on protecting user privacy" and they need to reassure their customers that data is protected.

Kay noted that customers of the tech giants "always felt they could trust the companies" and that there is a danger that "the customers may become cynical."

Kay said many facets of PRISM remain unclear, including why some firms have remained outside the system, and why Apple was not a participant until 2012, after the death of founder Steve Jobs.

"I imagine that Steve Jobs told the government to forget about it," Kay said.

Kay said that tracking technology has been around for some time, but that revelations of the PRISM suggest "a sea change."

"Even though this has been coming a long time, the 'total information awareness' world is upon us, and it arrived rather suddenly," he said.