A hot potato: Few apps experience the same levels of popularity and controversy quite like TikTok. It's already been banned by several US agencies and branches of the military, and now Joe Biden's presidential campaign staff have been told to stop using the application on work and personal devices.

TikTok was already incredibly popular before lockdown, which boosted its userbase even higher. With over 1.5 billion downloads, it was the seventh most-downloaded app of the 2010s, and has over 800 million monthly average users.

Despite its success, TikTok, owned by Beijing-based ByteDance, has been plagued with privacy issues, including a $5.7 million fine for illegally collecting the personal information of children. It's also been the subject of a US national security review, and banned by the Navy, Army, departments of State and Homeland Security, and the TSA. The White House is also considering a ban.

Now, former Vice President Biden's counsel, Dana Remus, has told staffers to "refrain from downloading and using TikTok on work and personal devices" due to concerns over security and data privacy. It comes after both the Democratic National Committee and the Republican National Committee also warned staff to avoid using the app.

It appeared that Amazon had banned its employees from using TikTok earlier this month over "security risks," but it later said the email it sent out to workers was an error. The app has also been caught copying iOS users' clipboard contents, something it claims is an anti-spam feature.

In addition to being banned by an increasing number of organizations, TikTok recently found itself kicked out of its biggest market: India. As tensions between the country and China rise, the former has banned 59 Chinese-made apps over security concerns.

TikTok, of course, continues to insist that it has never been a tool of the Chinese government, and would never provide the party with user information if asked. It seems, however, that not everyone believes the company.