This week Telefonica the owner of O2 have controversially announced they will start selling their O2 mobile customer data to third parties. Through Telefonica's Dynamic Insights business unit they are looking to drive revenue out of mining data to sell to third parties. They will take their phone network data and anonymise and aggregate it. The product will be called Smart Steps and will be sold to public sector companies to enable them to measure compare and understand what factors influence the number of people visiting a location. The aim is so that retailers can then make informed decisions on things like locations and opening times for shops. The big question is around privacy in the use of their customer data. People reacted very strongly when Google started using customer data for their targeted advertising and this seems to be in the same vein. As a mobile phone user I am not sure how happy I am effectively having my movements traced even though I understand this is just a bi-product of the phone network infrastructure. The real question is should Telefonica be allowed to use our movement data without consent and sell it third parties? My feeling is that as a user I should be able to opt in or out of this scheme as this would satisfy the privacy campaigners. How this would effect the quantity of data telefonica could sell I don’t know. I suspect there will be plethora of legal battles that will set the precedence in Big Data privacy over the coming months and years.