MarsBot - Local recommendations based on where you go. By Foursquare.
MailChimp Product Recommendations - Easily build automated personalized email marketing
Tripoto - Tripoto: Share and discover travel itineraries with global travel community
Travel TXT - Discover things to do when you travel via SMS.
World Brush - AR app where you paint on the real world for others to find
Depict.ai - Amazon-quality product recommendations for any online store