Every digital transaction and communication leaves digital traces and results in enormous collections of data about what we do and who we are. Your "big data" is being mined and analysed. This presents risks on privacy and personal security grounds, but also promises a new wave of productivity and technology-driven opportunities: smart cities, new knowledge, business opportunities etc. Discussing the many facets of this changing world, Peter Mares (ABC Radio National) introduces speakers Nicholas Gruen, Jane-Frances Kelly, David McCloskey and Peter Yates. The event is presented by Melbourne Conversations (City of Melbourne).