Virtually unknown outside its home country, Chinese news aggregator Toutiao is a household name inside it. Used by 600 million Chinese citizens, with 120 million logging in every day – covering almost the entire Chinese online population – Toutiao from the outside doesn’t seem all that different from most other outlets. But what makes the five-year-old start-up stand out is its ability to customise news selection for users through applying big data and machine-learning technologies.