Big Tech – too big to hide from?

We find out how Big Tech companies may know more about you - than you do.Host Claire Graham talks to the BBC's cyber correspondent for the BBC World Service Joe Tidy, about how Big Tech companies not only track what you do online – but what your friends do – and what your friends of friends do – to then target you through marketing.Billions of people access Big Tech companies on a daily basis – to interact on social media sites – but at what cost – your privacy?Produced by Cathy Young for the BBC World Service.