2. Tune Out Twitter, and Focus on ‘Facebook Moms’

A frequent criticism of Hillary Clinton’s 2016 campaign was that it was too focused on appealing to the elite, high-information crowd on Twitter, instead of paying attention to the much larger group of voters who get their news and information on Facebook. In 2020, Mr. Biden’s digital team was committed to avoiding a repeat.

“The whole Biden campaign ethos was ‘Twitter isn’t real life,’” Mr. Flaherty said. “There are risks of running a campaign that is too hyper-aware of your own ideological corner.”

As it focused on Facebook, the Biden campaign paid extra attention to “Facebook moms” — women who spend a lot of time sharing cute and uplifting content, and who the campaign believed could be persuaded to vote for Mr. Biden with positive messages about his character. Its target audience, Mr. Flaherty said, was women “who would go out and share a video of troops coming home, or who would follow The Dodo,” a website known for heartwarming animal videos.

One successful clip aimed at this group showed Mr. Biden giving his American flag lapel pin to a young boy at a campaign stop. Another video showed Mr. Biden, who has talked about overcoming a stutter in his youth, meeting Brayden Harrington, a 13-year-old boy with one. Both were viewed millions of times.