More and more of us have news fed to us from Facebook or we get it via Google. They are making it easy to find what we want, but they also influence which news and views we get - and the ones we don’t.
"All the time this year, I hear progressive folks say: 'I don't know a single Trump supporter. I don't see a single person arguing for Trump'. That's a problem because this is a country where four out of 10 people are voting for Trump," online entrepreneur and activist Eli Pariser told NPR in the US last month.
It is a problem he warned about five years ago in a book called The Filter Bubble.
Google’s personalised search function, he said, meant the results were echoing what people already knew and liked. Facebook's mysterious algorithms were steering users towards news reflecting their own preferences. Sources contradicting information that others have shared would not filter though into their bubble, he argued.
Five years later, experts are weighing the impact of the "filter bubble" on big political issues.
The online echo chamber
Cardiff University journalism professor Karin Wahl-Jorgenson saw it in effect during the UK's debate about Brexit.
"So much of the news coverage was emotional and politicised. The traditional role of journalism in exposing people to a wide range of variety of views and opinions was much more difficult," Professor Wahl-Jorgenson told Mediawatch.
UK internet activist Tom Steinberg posted evidence of this as soon as the EU referendum result was in.
"The filter bubble is so strong, and extends so far into things like Facebook's custom search that I can't find anyone who is happy - despite the fact that I'm actively looking to hear what they are saying," he said on Facebook (where else ... )
"We're getting countries where one half just doesn't know anything at all about the other," he said.
Legacy media cries foul
This prompted the editor of the UK newspaper - and pioneering global multimedia news outlet - The Guardian to say: "Social media has swallowed the news".
In a long essay - widely shared on social media and as an audio podcast - Katherine Viner argued online platforms don’t just spread the news with unprecedented efficiency, they skew the supply of it - especially to the 1.7 billion people around the world now using Facebook.
But “filter bubble” cannot easily be burst.
"This is a problem ... baked into the very idea of social networks that are designed to give you what you and your friends want to see," she wrote.
The likes of Google and Facebook are so popular media companies can’t ignore it. They drive the bulk of of the online traffic to their websites, which in turn brings them income from online advertising. It’s not nearly as much as they used to get from old fashioned ads before the internet swallowed up much of the business - but its crucial income all the same.
Facebook takes over
Facebook launched in 2004 and has become the dominant way for people to find news on the internet in many countries - including New Zealand.
A Colmar Brunton survey of 1000 people last month concluded 80 percent of New Zealanders are on Facebook - including nine out of every 10 people aged between 18 and 39.
Online users also get news by searching for it. Overwhelmingly, they choose Google for that.
A news story high up in Google's search ranking can be lucrative. Some news organisations now craft their news with that in mind.
"Some news organisations are putting in key words proven to be popular, often in headlines or right at the start of the article," said Melanie Bunce, a New Zealander who has researched this at City University's journalism school in London.
Sometimes journalists are told to include certain words, she said, or editors may insert them afterwards.
It can be obvious if the Daily Mail puts David Beckham in a story where he doesn't belong, she said, but usually online readers wouldn't know "search engine optimisation" was happening.
But is this necessarily bad for journalism?
"It can help people find stories they're looking for, but it can create an association between topics that don't have a natural association. Right now that could include news stories about immigration and refugee issues. There are similarities but the two issues can be confused," Dr Bunce said.
From upstart start-ups to digital dominance
When Facebook and Google were founded in the early 2000s, Dan Gillmor was a columnist at the San Jose Mercury News in California, covering Silicon Valley. He wrote about the dot-com boom close up, and the subsequent bust.
Indeed, he had a crack himself.
He left the paper in 2005 for a journalism start-up called Bayosphere to make it easier for ordinary people to report and publish online. It didn't last long.
Did he foresee that other small start-ups - Facebook and Google - could one day become crucial parts of the modern news media?
"It was pretty clear even in the 1980s that we were moving towards something that would be very different,' he told Mediawatch.
"But Facebook is becoming a global arbiter of what is important. It's great technology but it's got to the point where it has too much power. Journalists who pour their work into Facebook and don't understand what it means for journalism don't understand they are making a grievous mistake."
Unlike The Guardian's Katherine Viner, Professor Gillmor doesn't blame Facebook or Google for "disrupting the truth".
"Poisoned public discourse goes back a long way. Tabloid newspapers and broadcasts over 50 years or more have not been interested in the truth," said Professor Gillmor, who now advises media start-ups and teaches ‘Digital Media Entrepreneurship’ at the Walter Cronkite School of Journalism in Arizona.
In a recent article called: Journalists: Stop complaining about Facebook, and do something about it Dr Gillmor said media companies should not "capitulate" to Facebook's dominance:
"An enterprise that would become the primary newsstand for journalism and would be free to pick the winners via special deals with media people and tweaks of its opaque algorithms. If this is the future, we are truly screwed.
- Dan Gillmor
Should the news media turn their backs on Facebook?
"The dependence is so great they cannot go cold turkey," he said, "but I hope over time the media can get out of a major trap. I don't think Facebook people are evil, but they have the power to determine the boundaries of freedom of expression of a lot of people."
Professor Gillmor said he thought Facebook's ambitious founder and boss Mark Zuckerberg may have over-reached. He has said Facebook should be “like electricity” - a public utility that we cannot do without.
"That was a tactical error. We regulate public utilities. If Facebook wants to be one, they have to be a 'common carrier' not allowed to exclude others from a network."
In some parts of the world Facebook is offering free access to the internet. The catch is that Facebook is the point of entry.
"In some countries Facebook is literally the internet because of deals that have been made with local telcos.
"India said no, which was a good decision. But is some free internet better than none? It's elitist to say 'no' - but we should not allow anyone to become the internet," Professor Gillmor said.
While search engines and online social media have made it easier for people to choose news and views from publishers all over the world, research shows many people getting news on their personal Facebook feeds often take no notice of where the news comes from.
Columbia University’s Tow Centre says news publishers have lost control over the distribution of their own journalism and their brands are being destroyed.
Just how much of that control now rests with Facebook was made clear in late June.
In a statement headed “Building a Better News Feed for You” Facebook announced “an update that helps you see more posts from your friends and family”.
This sudden tweak of the mysterious algorithm to downgrade news panicked media publishers.
“For the first time, Facebook stated explicitly that it didn’t care too much about news,” said French technology and business reporter Frederic Filloux.
Follow the money
But even if they don’t care about news as much as the primary mission of “connecting people” Facebook is making money out of media companies’ news.
Indeed, Facebook is making more money than most financial analysts thought possible.
Last month, Facebook announced its revenue was up to almost $US6.5 billion.
The same day the parent company of Katherine Viner’s Guardian announced its biggest ever pre-tax losses: $US265m for the year.
One bright spot was its membership scheme. 50,000 people have signed up to pay monthly fees to support The Guardian's journalism.
But that is a drop in bucket compared with Facebook's membership of 1.7 billion - announced by Mr Zuckerberg the same day - along with those staggering income and profit stats.
Mr Zuckerberg also repeated the phrase that’s become Facebook’s corporate mantra: “Our journey is only one percent done".
Struggling news media companies are wondering what will be left of their business when Facebook’s further down the track - and the story of Facebook so far tells us the future it envisages may be closer than we think.