Why people share on social media

Among New York Times articles, the ones with more practical value were more likely to make the paper's most-emailed list, and by about the same margin as articles that caused awe. Jonah Berger, who has studied sharing for more than a decade, explains it this way in a 2025 review: passing on useful information makes the person who passes it on seem knowledgeable and helpful.

I've always been the one hitting the follow button. What got me into studying how people behave on social media was realizing that the accounts I followed were run by people, and so was mine, and the people following me were people too. People want to feel knowledgeable, included and important. Sharing is where you can watch the first of those happen: someone sends your post because it makes them the friend who knew something.

What the New York Times data showed

Berger and Katherine Milkman tracked almost 7,000 articles over three months in 2008 and had a few thousand of them coded for the emotions they caused and for how useful the information was. An article one standard deviation more useful than average (a standard deviation is the typical distance from the average) had about a 30 percent better chance of being one of the most emailed. Awe raised the chance by about the same amount and anger by 34 percent, and sadness lowered it by 16 percent.

Sharing with one person is different from posting to all your followers

An email goes to one person. In 2014, Alixandra Barasch and Jonah Berger ran six experiments on how the size of the audience changes what people share. In one, people imagined either posting a Facebook status update to all their friends or writing on one friend's wall.

Posting to all their friends made people think more about themselves and how they'd come across, and it made them more careful to avoid sharing anything that would make them look bad. Messaging one friend made them think more about that friend, and their preference for useful content was stronger: on the study's rating scale, useful content beat less useful content by 5.12 to 2.95 when sharing with one friend, and by 4.50 to 2.97 when posting to all their friends.

Berger and Milkman saw the same split in their own data. On the paper's most-blogged list, where people were posting publicly, useful articles were slightly less likely to appear.

What the platforms count

Instagram's feed ranking names sends among its signals: whether someone opens the share sheet and sends a post to a person. For Reels, Meta names whether someone shares the reel off Instagram. So the one-to-one share that the research ties most closely to useful content is also something Instagram measures directly.

Sources: Instagram Feed ranking (updated June 29, 2026) and Instagram Reels ranking (updated November 11, 2025), Meta Transparency Center.

Where the research stops

• The New York Times study is about news articles sent by email in 2008, not posts on Instagram or TikTok.
• Barasch and Berger's outcomes were mostly people's ratings of how willing they'd be to share, in imagined situations, not what they actually shared. They also found that "useful" and "makes me look good" weren't the same thing in their materials.
• Berger's 2025 review sums up other studies. The idea that people share to look knowledgeable is the explanation those authors give, and it hasn't been measured directly on a social platform.

What to do with it

• Name the one person a follower would send it to before you post: a coworker who keeps asking the same question, a friend opening a shop, a sister with a toddler. If you can't name anyone, make the post more useful to that person.
• Make the useful part easy to pass on. A single number, a three-step fix or a short list a person can forward without explaining it.
• Let the sender look good. Content that would make a follower look careless if a friend read it is content they won't send.
• Pair use with feeling. Useful and awe-inspiring each raised the chance of being emailed by about the same amount, and a post can do both.

Sharing is one thing a follower can do with your post. Commenting is another, and it runs on a different motive: how to get people to comment.

Sources: Berger & Milkman (2012); Barasch & Berger (2014); Berger (2025), "What Gets Shared, and Why?", Annual Review of Psychology; Meta Transparency Center. Every study was read in full before it was cited here.