Tom Cruise

You may remember the scene in the movie "The Minority Report" when Tom Cruise's character enters a Gap store and is greeted by a hologram of a store associate who welcomes him back to the store and asks how his last purchase — assorted tank tops — worked out for him. When this movie was released in 2002, this personalized in-store experience seemed far into the future, but it's now almost upon us.

In the often-referenced sci-fi movie "Minority Report," Tom Cruise walks into a Gap, is instantly recognized and receives tailored purchase recommendations. But what if predictive technologies...