More than two-thirds (67%) of American consumers use their mobile phone to shop. Not surprisingly, mobile usage skews even higher for the coveted younger Millennial demographic (ages 18-29), with nearly 8 out of 10 (79%) shopping on their mobile phone.

That's according to a 2016 study from RichRelevance, which explored which mobile and location-based marketing innovations consumers found "creepy or cool." The study discovered that consumers have mixed feelings about proximity marketing and in-store location awareness. While consumers now expect to use their mobile phones as part of the in-store experience, they are most open to mobile and digital innovations that allow them to choose when and how to engage.

They are less comfortable with technology that can identify them individually without their knowledge or opt-in, such as in-store facial recognition. Other capabilities, such as the ability to access product information and reviews or recommendations and in-store discounts, were see as "cool."