The app earns its name from its other highlight, personalization. It generates a custom shopping "district" based on both your favorites and historical shopping data (over 1 billion sessions, ShopRunner said) that shows you what's trending. Yes, it's another instance of a company tracking your shopping patterns, but it might be worth the effort if you either don't know where to start or just need a brief flash of inspiration.

This probably won't make Amazon too nervous when it's making plenty of money and expanding its own fashion efforts. However, it's a good example of how big names can potentially circumvent Amazon -- by uniting under a shopping destination that still gives them plenty of control.