ByteDance took large amounts of content from both platforms without their knowledge or consent and published them via fake accounts to TikTok, according to information from four former employees.

They said that ByteDance used the content to train its algorithm that recommends content to US users based on their interests. The Chinese equivalent of the algorithm would be used by TikTok.

The approach was part of Beijing-based ByteDance's strategy to expand its Flipagram platform. ByteDance acquired the video app in January of last year. The service was shut down in late 2020 according to a cached version of the announcement on the official website.

According to the former Bytedance employees who spoke to the website, Bytedance used data from other social media to populate its site.

Bytedance first created fake accounts and populated them with short videos from its Chinese apps that were not too Chinese, but when that strategy failed to attract new users, ByteDance started taking short-form videos, usernames, profile pictures.

ByteDance did not respond to the request for comment.

The China-based engineering team that was in charge of growth hacking at Flipagram scrapered more than 10,000 videos a day. Sources told the outlet that ByteDance used the content to fine tune its algorithm for US users.

ByteDance's tactics didn't go unnoticed. Some users of the photo sharing service complained that their content appeared on the photo sharing site without their knowledge. Other users complained that they weren't able to uploaded their photos to their Flipagram accounts. Some worried that they were being impersonated, while others were concerned that their children's content was published on an app that they were not familiar with.

ByteDance was in legal trouble for violating intellectual property rights. Last year, Chinese social media and gaming giant Tencent launched a series of lawsuits in China against ByteDance.