Facebook sought to allay fear and suspicions surrounding biases in its popular “Trending Topics” News Feed Wednesday by outlining a set of values the social network says it uses when curating news content.

“We don’t favor specific kinds of sources — or ideas,” Adam Mosseri, Facebook vice president of product management wrote in a blog post Wednesday. “Our aim is to deliver the types of stories we’ve gotten feedback that an individual person most wants to see. We do this not only because we believe it’s the right thing but also because it’s good for our business.”

The statement comes in response to a Gizmodo article last month in which former Facebook employees said they suppressed content from conservative news outlets in favor of liberal ones — an allegation the company has been working to dispel ever since.

“We are not in the business of picking which issues the world should read about,” the blog post reads. “Our integrity depends on being inclusive of all perspectives and view points, and using ranking to connect people with the stories and sources they find the most meaningful and engaging,”

Mosseri goes on to explain how the News Feed users see is curated based on their individual preferences, ranking from top to bottom content from friends and family (which will dominate user feeds starting Wednesday via forthcoming updates), informative posts and lastly, entertaining posts. The system is constantly adjusting based on users’ activity, and Facebook’s work on News Feed is only “1 percent finished,” according to the company.

The company pledged to “be as open as we can” with regard to sharing how News Feed works in the future.

Facebook’s campaign to convince conservatives otherwise with statements, briefings and face time with executives — including COO Sheryl Sandberg — appears to have had little impact on their concerns and those of others. The National Newspaper Publishers Association (NNPA), which represents hundreds of black-owned media companies, expressed their own concerns Monday at the lack of knowledge surrounding how Facebook ranks content, and called on federal regulators “to bring some much needed transparency to the new media king.”

“The tech company isn’t transparent in its methods. So we don’t know whether the viewpoints of black publishers are heard or if there is a bias against our views,” NNPA representatives wrote. “Without knowing how Facebook’s ‘Trending Topics’ or other algorithms are used in promoting stories, the owners of black-owned newspapers, magazines and other media are left only to wonder why the stories our outlets produce are relegated to the margins – if they are acknowledged at all.”

Experts on a panel at New America, a Washington-based policy think tank, expressed similar concerns about Facebook and Google’s impact on journalism Wednesday.

Martin Moore, Director of the Centre for the Study of Media, Communication, and Power at King’s College London said social media networks like Facebook don’t see themselves as publishers, despite the growing influence they hold over mainstream media, and as such, “don’t subscribe to the same practices and values as a news organization.”

“They don’t, for example, see it as their role to ensure a diversity of news — the way the algorithms are structured results in the opposite,” Moore said. “As the editor of Buzzfeed said last week, ‘the publishing rules of these social media platforms are rooted in no clear precedent, tradition or philosophy and seem to be improved in reaction to circumstance.'”

Moore said Silicon Valley’s views on freedom of speech and other key democratic values and journalism ethics raise questions about their viability in the news sphere.

“How would Facebook respond if a news organization sought to publish Snowden-like leaks via Facebook instant articles?” Moore asked. “Are we confident that Microsoft would not allow public authorities to listen to conversations between a journalist and a source on Skype?”

The web giants’ don’t define themselves by their independence from the state and don’t see it as their role to report on public affairs, making them unfit sources for news, according to Moore.

“For these reasons — though we’re coming to rely on them for our news — we can’t rely on them for our news,” he said.

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