In a self-critical appraisal of itss impact to date, Facebook acknowledged today that social media can have a negative impact on democracies, but added that it will aim for the good to outweigh the bad.

"I wish I could guarantee that the positives are destined to outweigh the negatives, but I can't," Samidh Chakrabarti, a Facebook product manager, wrote in his post.

In 2016, we at Facebook were far too slow to recognize how bad actors were abusing the platform. The 2016 US presidential election brought to the fore the risks of foreign meddling, "fake news" and political polarization.

Chakrabarti expressed Facebook's regrets about the 2016 U.S. elections, when according to the company Russian agents created 80,000 posts that reached around 126 million people over two years.

The company should have done better, Chakrabarti wrote, and he said Facebook was making up for lost time by disabling suspect accounts, making election ads visible beyond the targeted audience and requiring those running election ads to confirm their identities.

In the battle against fake news, for example, Facebook has tried several different strategies, such as working with third-party fact-checkers to mark dubious articles as "disputed," then deciding to offer up "related article" suggestions instead. The company will also start polling users about the trustworthiness of sources, with the goal of using that data to guide rankings in the news-feed algorithm.

"Even with all these countermeasures, the battle will never end," Chakrabarti added. "Misinformation campaigns are not amateur operations. They are professionalized and constantly try to game the system. We will always have more work to do."

Facebook also talked about the challenge of working with government leaders who harass their own citizens. Chakrabarti wrote about a citizen in one country who told Facebook that after he posted a video critical of the government, the police visited him to inspect his tax compliance.

There are also officials in "more open societies" who "write hateful posts that make enforcing our Community Standards challenging," Chakrabarti said. "So far, we've kept such posts up on our platform since we view them as newsworthy information that citizens deserve to know."

Last month, Facebook said "passively" consuming social media can be bad for mental health.

Chief Executive Officer Mark Zuckerberg has been trying to adjust Facebook's goals to make sure the site has a positive impact.