As marketers and customer experience professionals around the world prepare for the implementation of the EU's General Data Protection Regulation (GDPR), many want to dig deeper into the regulation to ensure compliance and best practices are in place.With that in mind, we're kicking off a series of posts designed to ground readers in in GDPR's data fundamentals, the building blocks of the regulatory framework. And we'll begin in a pretty obvious place: what is customer data?It's a simple....