Important people at Meta, like CEO Mark Zuckerberg and the head of Instagram, Adam Mosseri, believed that TikTok was more successful than Meta in areas where Meta expected to do well. This information is from a document in the US government's legal case against Meta, which was made public on Monday.

The document from February 2022 has talks between some Meta bosses about Facebook and Instagram's plans and place in the market. In one message, Zuckerberg said Facebook is a competitor that has lost popularity and is not growing as fast. He also said TikTok helps people feel connected because friends see the same popular online content.

Mosseri agreed that Facebook is now a competitor, saying it's not the main way people find new things anymore. He suggested that YouTube might be the most popular way to discover things now, but he believed TikTok would become more popular than YouTube eventually, based on the information Meta had.

Mosseri wrote that Facebook's best plan is to be the main place where people find new things. However, he found it interesting that TikTok, which only uses videos, is much more successful. He guessed that TikTok is making the social mobile market bigger and also taking users from TV, long videos, and Netflix.

Mosseri's prediction was correct. One study showed that in 2021, people in the U.S. spent more time watching TikTok than YouTube on average. A different study in 2023 found that children and teenagers spent 60% more time on TikTok than YouTube. Last year, to compete with YouTube, TikTok started letting users upload videos up to 60 minutes long.

This week, Netflix added a feature similar to TikTok in its phone app, showing short vertical videos of suggested content that is different for each person.

In the trial, the US government is trying to show that Meta broke rules about competition by buying companies like Instagram and WhatsApp. They say Meta did this to become the only big social media company. A document like this could make their case weaker because, inside Meta, leaders were talking about how Facebook was losing a lot to TikTok.

For example, Zuckerberg said that even though Facebook had the most daily or weekly users, people were not spending the most time on it anymore.

He also said that TikTok can give people a feeling of shared experiences. For example, if you and your friends like the same topics, you will probably see similar content on TikTok, he explained.

"This makes it social," the CEO said, "because you can just assume your friends have seen it instead of sending it to them. It would be great if we could get to this level with topics and content on FB that is not connected."

Several other executives also contributed their perspectives.

Will Cathcart, who is in charge of WhatsApp, said that when people comment on a TikTok video about a certain topic, the app's system learns what they like. This means it will show them and other people who commented similar videos later.

Stan Chudnovsky, who was a Vice President and General Manager at Meta, said that Meta had started to compete in a market that was now divided, and many companies were reducing their growth.

"Just adding a new feature, like we did with Stories, isn't enough anymore," he said. He explained that people have many other places to spend time online, mentioning popular apps in the U.S. like TikTok and Twitter.

John Hegeman, who was in charge of ads and is now the head of sales, agreed that TikTok was clearly ahead in areas like short videos, how content is ranked, and tools for making videos. But he thought Meta could catch up if creators also posted their videos on Reels.

However, he wasn't sure how far behind Meta was in areas like machine learning, technology, and tools for making things. The document shows that Meta thinks Facebook is not the strongest competitor in the social media market.

This document isn't the only one that has come out during the trial showing Meta is afraid of competition. Zuckerberg himself said last month that TikTok doing well was a danger to Meta's business and made it grow slower.