In the past month three of the world’s largest tech firms have been hit with legal actions that could lead to billion-dollar damages suits for alleged violations of Europe’s privacy law, the General Data Protection Regulation (GDPR). Unusual for Europe, the complaints are led by a consumer rights group and a U.K. citizen rather than regulators.

Neil Hodge is a freelance business journalist and photographer based in Nottingham, United Kingdom. He writes on insurance and risk management, corporate governance, internal audit, compliance, and legal...