There’s almost always some trade-off between privacy and personalization; this has been true for every generation of technology. Retailers need to move forward with transparency, respect, and security as their priorities. They also need to show value. Google has done this well, not just with personalized search results but also with services such as Google Now, which integrates with your calendar and Google Maps to alert you that traffic to your meeting is heavier than usual and tells you when you should leave the office to arrive on time.
From an HBR article How Predictive AI Will Change Shopping. It makes lo.ts of good points about the use of predictive analytics to enhance the shopping experience (which will certainly continue to grow), but it's also very tied to the amount of information that you're willing to share (perhaps unknowingly).
