At the heart of TikTok is its algorithm, a set of instructions which determines which content is presented to users, based on data about how they engaged with previous material.
Users are offered three main feeds on their app – Following, Friends and For You.
The Following and Friends feeds present users with content from people they have chosen to follow and who follow them back, but the For You feed is automatically generated by the app.
This curated feed has become the main destination for users looking for new content, and creators hungry for the millions of views TikTok videos can clock up if they go viral.
Critics say the app collects more data than other social media platforms in order to power its highly personalised system.
This can include information about users’ location, device, the content they engage with and keystroke rhythms they exhibit while typing.
But popular social media apps such as Facebook and Instagram collect similar data from users.