Personally, I really like location-aware app features. My favorite is search suggestions. If I'm in BestBuy and I open the app to the products section, chances are I want more details or reviews on the product I'm standing in front of. Why make me search for it? Have "smart suggestions"

The grocery store example is something I've been debating creating for myself. I have a hunch if I stick Estimote stickers underneath stuff at my grocery store no one will find them for a while.