What are some of the key privacy concerns around the use of big data?

There are a few concerns for privacy when it comes to big data: customer protection, regulation compliance and usability. Ultimately, a good privacy policy for big data provides the maximum protection for your customers, it's compliant with the regulations that the product is subject to (like HIPAA, GDPR, etc.) and provides an incredibly useful product as well by leveraging the data in a responsible way. To achieve all three is at times incredibly difficult, but is usually possible if thought about in the right way. There exist techniques like anonymization and privacy-enhancing technologies that allow products to achieve all three goals easier than before. It's incredibly important that privacy is thought of upfront, like security, when designing your big data systems, as it can be incredibly expensive to add later.