TripAdvisor is the largest travel reviews website in the world, boasting over 60 million members, and making nearly US$1 billion in revenue annually. Customers of hotels, restaurants and other attractions add 115 comments to the site every minute. According to Outside Online's Tom Vanderbilt, "the site is now so big that its reviews can shift the tourist economies of entire countries." Tourism Economics has conducted a study of TripAdvisor, finding that user-generated content was directly related to 1.7 billion pounds of tourism spending in the UK; making up around 2.2% of all tourist spending in 2012. According to an internal TripAdvisor study, hotel owners who reply to commenters are 20% more likely to get bookings. Today, TripAdvisor lists over 890,000 hotels, holds one of the largest collections of travel photos on the internet and features accommodation in more than 45 countries. Click here for more insights.