Mark Zuckerberg's former mentor has spent a week attacking Facebook for becoming 'toxic'

Roger McNamee, an early Facebook investor and ex-mentor to CEO Mark Zuckerberg, has spent a week attacking his former protégé and his company for harming users and for spreading fake news.

McNamee has written articles for The Washington Monthly, The Washington Post, and The Guardian over the last week, accusing Facebook of ignoring "bad actors" who manipulate its platform.

McNamee said Zuckerberg should appear before Congress to justify Facebook's "refusal to accept responsibility" for harming users.

He wrote in The Washington Monthly that he flagged misinformation around the US presidential elections to Facebook in early 2017, and that the firm didn't take his concerns seriously.

"The platform was being exploited by a range of bad actors, including supporters of extremism, yet management claimed the company was not responsible," he wrote. "Facebook’s users, I warned, might not always agree. The brand was at risk of becoming toxic."

In The Washington Post, McNamee argued that Facebook was "tailor-made for abuse by bad actors" and that users should expect more fake news and manipulation of elections.

He wrote: "The same tools that make Facebook so addictive for users and so effective for advertisers are dangerous in the hands of bad actors.

"And thanks to automation, Facebook cannot currently prevent harm. It will happen again and again until Facebook takes aggressive action. The problem cannot be fixed by hiring contractors to review problematic posts. The company needs to change the priorities of its algorithms and retool its business model."

Facebook has faced criticism for working as a platform for alleged Russian interference in the US election. Evidence has shown that accounts linked to Russia sought to exploit racial divisions in the US and used Facebook's targeted advertising tool as well as events on the site to reach voters.

Zuckerberg said in a live video on September 21 that "I care deeply about the democratic process and protecting its integrity. I don't want anyone to use our tools to undermine democracy."

And Facebook recently announced that it would tweak its news feed algorithm to prioritise posts from friends rather than content from businesses and media companies. "We feel a responsibility to make sure our services aren't just fun to use, but also good for people's well-being," Zuckerberg said in the announcement of the change.

According to McNamee's version of events, he received a call from Facebook's then-chief privacy officer Chris Ziegler in 2006. Ziegler was hoping McNamee, as an experienced investor and disinterested party, could advise a young Mark Zuckerberg about whether to sell Facebook or not. McNamee met with Zuckerberg and advised him not to sell the company. "I was convinced that Mark had created a game-changing platform that would eventually be bigger than Google was at the time," McNamee wrote.

What followed, he said, "was the most painful silence of my professional career."

As it happened, Yahoo had just offered $1 billion (then around £509 million) for Facebook. Though everyone was advising the opposite, Zuckerberg took McNamee's advice and turned the offer down. McNamee went on to mentor Zuckerberg and invest in Facebook through Elevation Partners, the investment firm he cofounded with U2 frontman Bono.