NYT:

But as the events of just one day — Feb. 12 — at Facebook showed, although the companies are better equipped to deal with the types of interference they faced in 2016, they are struggling to handle the new challenges of 2020.

Their difficulties reflect how much online threats have evolved since the 2016 election. Russia and other foreign governments once conducted online influence operations in plain sight, buying Facebook ads in rubles and tweeting in broken English, but they are now using more sophisticated tactics such as bots that are nearly impossible to distinguish from hyperpartisan Americans.

More problematic, partisan groups in the United States have borrowed Russia’s 2016 playbook to create their own propaganda and disinformation campaigns, forcing the tech companies to make tough calls about restricting the speech of American citizens. Even well-funded presidential campaigns have pushed the limits of what the platforms will allow.