Here’s the latest activity, and what firms including Facebook Inc. and Twitter Inc. are doing about it, updated through Tuesday:

Facebook Pulls Controversial Ad Backed by Trump (1:25 p.m. ET)

Facebook followed Fox News and NBC in pulling a controversial TV commercial about the migrant caravan after an online backlash that included protests from Hollywood celebrities.

The Republican campaign spot, backed by President Donald Trump, says the migrant caravan is filled with “dangerous illegal criminals.”

“This ad violates Facebook’s advertising policy against sensational content so we are rejecting it,” a company spokeswoman said. “While the video is allowed to be posted on Facebook, it cannot receive paid distribution.”

Donald Trump Jr. @DonaldJTrumpJr CNN refused to run this ad… I guess they only run fake news and won’t talk about real threats that don’t suit their agenda. Enjoy. Remember this on Tuesday. #vote #voterepublican

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Facebook Changes How It Pays Fact-Checkers (1:08 p.m. ET)

The social-media giant hasn’t ever wanted to directly fact-check stories, so it relies on third parties to do the work. Now it’s testing a new way to reward partners, including PolitiFact and Snopes. The company usually pays them on a contract basis, but now it’s beginning to pay per-story. This gets Facebook more involved in identifying which content is checked first, and encourages fact-checkers to work quicker and focus on the most-important articles first.

Facebook confirmed it’s piloting a new process where it gets highly likely misinformation to U.S.-based fact-checkers faster, to reduce the time to address problematic content, a spokeswoman said. It can take these groups several days to debunk something, and by that time the piece has often already gone viral and caused damage.

Facebook said it’s picking this priority content partly based on the number of times users call out the story for being unbelievable. “The things that we flag for fact-checkers in these higher-signal escalations are items that we have a higher confidence to be false,” the spokeswoman said. “This method is lower volume but higher precision, and we flag a small number of high-confidence items this way to encourage fact-checkers to review these items first.”