Expedia led the pack in 2014 when it unveiled such a product in the hotel sector. Customers who book via Expedia are asked - via email and the Expedia app - three questions after check-in: How was the check-in experience, how's the room, and are you happy with the location? They can respond with a smiley or frowny face, and elaborate any concerns in greater detail. The information is then sent back immediately to the hotel property. "It's been a feature that's been really well received," says Clint Hayashi, Expedia's EMEA head of communications. "Hotels love it because they can mitigate any issues in real time, and there isn't something that festers." Get the full story at CNN.com