TikTok, also known as Douyin in China, is a popular social media app that allows users to watch, create and share 15-second videos shot on cellphones. Besides adding various effects like filters, background music and stickers to their videos, users can also collaborate on content while being in different locations and create split screen "duet" videos. The platform is said to have an addictive quality and high levels of engagement with its personalized feeds of quirky and creative short videos.

The name TikTok is onomatopoeia for the sound of a ticking clock and represents the short format of the videos. Launched by Chinese startup ByteDance in 2016, TikTok absorbed the similar Chinese video app musical.ly in August 2018. Lip sync-app musical.ly was bought by ByteDance for an estimated $1 billion the previous year.

ByteDance is reportedly valued at $75 billion, making it the most valuable startup in the world. It owns several other apps and has raised $3 billion from investors, including SoftBank Group, KKR, K3 Ventures, TCV and General Atlantic, according to Crunchbase.

TikTok hit 500 million active monthly users worldwide in July last year, according to ByteDance. Market analyst Sensor Tower has said the app crossed the one billion mark for worldwide installs on the App Store and Google Play in February. Besides China, it enjoys immense popularity in India, which is where a quarter of its downloads have come from. About 96 million of the downloads have come from the U.S..The company currently has offices in Beijing, Berlin, Jakarta, London, Los Angeles, Moscow, Mumbai, Sao Paulo, Seoul, Shanghai, Singapore and Tokyo.

TikTok recently began testing ads and also makes money on in-app purchases. Users can buy coins to tip their favorite creators on the platform. They spent $6 million on these gifts in December, according to Sensor Tower.

A social media trend that has helped the app gain attention worldwide is viral meme challenges. The company has also pursued an aggressive marketing strategy that involves getting popular celebrities to use the app and advertising on competing platforms like Facebook Inc.'s (FB) Instagram and Snap Inc.'s (SNAP) Snapchat. Facebook launched a TikTok clone called Lasso late last year.