European privacy regulators could be about to throw a spanner into the works of attempts by social networking sites such as Facebook to find new ways to increase profits as they try to restrict the way internet groups release personal data.

The European move marks the first attempt by regulators to address the “open” internet platforms that the social networks, led by Facebook, have rushed to create. By letting other applications ride on top of their systems, tapping into personal data about their members, the networks have sought both to tie in users for longer and create money-making opportunities.