By Chris Vallance
By Joseph Lee
Technology reporter Zoe Kleinman keeps a video diary of the times she shares data with tech companies.
By Richard Baimbridge
By Alys Davies
By Lucy Hooker
Business reporter, BBC News
By Andrew Clarance
BBC News, Delhi
If Google knows everything you have ever searched for, it most likely has a detailed catalogue of your interests, hopes and fears. Facebook knows who your friends are, what you like and what you talk about online.
Online data scandals have raised concerns about the power that information brings.
Some people are now choosing to go with smaller rival companies, which promise greater privacy. Read more here.
Amy Webb is a renowned futurist - she looks back at the past and scours data to figure out what might be round the corner.
Data lawyer, Ravi Naik, warns we are entering an era where tech companies have as much, if not more, power than some states and there needs to be accountability