Usability 
The venerable (founded in 2000) crowd sourced travel review and recommendation site TripAdvisor, now has a mobile edition with hotel, restaurant and attraction reviews by the TravelAdvisor community.
The site is compatible with most mobile browsers and is location aware on the iPhone and Android. Listings include reviews, a numeric ranking compared with similar, nearby establishments, driving directions and click to call numbers. Hotel listings include links to reserve a room using Hotels.com, Expedia or Orbitz. Source: IntoMobile