Sir Tim Berners-Lee was speaking at a keynote speech at IPExpo Europe in London.
He hit out at the notion that data belongs to corporations like Facebook and Google who collect it and then use it to make money out of everyone.
He said that using big data for advertising purposes gave him a queasy sensation and rather than big data we should be interested in rich data.
He told the conference that big companies are, essentially, spying on us all and this is a real threat.
Collecting your own data from different gizmos you use and different transactions you make gives you a perspective on yourself that is much more valuable than feeding that data to large corporations.
Berners-Lee described what would become known as the world wide web 25 years ago.