But how much information is potentially available on the average smartphone user? As an experiment, I decided to access my own data files from third parties to find out.
The results were surprisingly revealing, showing my favourite lunch locations, sporting preferences and even the methods I use to get our newborn son to sleep at night.
All companies in the EU will now give users data held on them on request, but the telecoms groups have come under particular scrutiny given how much information they hold is shared with government departments.
Even a relatively superficial trawl of the data they hold can be used to compile an accurate log of movements and communications.
A request to my mobile operator resulted in hundreds of pages of information, which would also be accessible to public sector bodies and civil servants under the Regulation of Investigatory Powers Act 2000 in the UK. The information included who I called, texted or emailed, as well as when and where I was when messages were received, but did not stretch to the content of these communications. The telecoms groups need to keep records for up to a year and will hand over details if requested by a government body with sufficient authority. Last year, public authorities submitted 570,135 requests for communications data.