Usability 
Mogoso is a search site that simultaneously searches Yelp for stores and restaurants and also does an Amazon shopping search. The results link to reviews Amazon or Yelp reviews. I find Mogoso's search interface and results pages cleaner and and easier to navigate than either Amazon's or Yelp's. For one thing, searching for restaurants by zip code actually works on Mogoso by returning results by distance, Yelp first returns results sorted by rating from throughout the metropolitan area, you have to click a link and wait to find the nearest ones.
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