(Reuters/Catherine Benson)

What  are the biggest threats to the Internet in the next 20 years? According to experts canvassed  by Pew, the biggest threats aren't a rise in hacking attacks or new waves of Internet crime. They're government and big online corporations.

Control and consolidation were the top threats for experts canvassed by Pew's Internet and American Life Project in a study published Thursday. The think tank asked more than 1,400 experts -- academics, theorists and those who work in the technology industry -- to weigh in on what risks the Internet faces through 2025.

The majority pointed to government surveillance, restrictive regulation and corporate greed as the things most likely to kill the idea that the Web is a  free-flowing network of information. Plenty expressed concern that the Internet will fracture due to government policies, such as those that limit access to the Web as some governments did during the Arab Spring, aggressive intellectual property laws or even well-meaning policies in Canada and Australia that aggressively filter all Internet traffic to combat child pornography. These efforts, experts said, cross the line -- or at least flirt with it.

Paul Saffo, managing director at Discern Analytics, said: "The pressures  to balkanize the global Internet will continue and create new uncertainties. Government will become more skilled at blocking access to unwelcome sites."

Experts were also quick to point out that recent revelations in the wake of Edward Snowden's leaks about the National Security Agency and disclosures about the data that companies are vacuuming up threatens to erode trust in the greater Web.

"Because of governance issues (and the international implications of the NSA reveals), data sharing will get geographically fragmented in challenging ways. The next few years are going to be about control," said danah boyd, a research scientist for Microsoft.

Speaking of control, several experts also noted that more corporate control over the Internet could also choke off the free flow of information. Many expressed support for network neutrality -- the idea that all content on the Web be treated the same -- and raised alarms about where they see the issue going right now.

"It is very possible we will see the principle of net neutrality undermined," said P.J. Rey, a PhD candidate in sociology at the University of Maryland. "In a political paradigm where money equals political speech so much hinges on how much ISPs and content providers are willing and able to spend on defending their competing interests. Unfortunately, the interests of everyday users count for very little."

And others argue that some of the biggest threats come from Internet-based companies themselves, such as Facebook, Google and Apple, because of their unprecedented reach and vast banks of user information.

"There should be many information sources, more distributed and with less concentration of control," said Marc Rotenberg, president of the Electronic Privacy Information Center. "The current model is to find an innovation with monetizing potential, incorporate, demonstrate proof of concept, sell to an Internet giant and walk away. This will not end well."