Hotel and Travel sites Expedia and Priceline are clamping down on fraudulent reviews on their website reports Yahoo News. "We have certainly seen instances with other properties where insiders have put reviews up for a particular hotel or a particular thing and it's not a legitimate review," said Jeff Boyd, Priceline.com's chief executive.

A lot can be at stake with fake reviews when Expedia's TripAdvisor, the largest hotel review site with more than five million reviews, says that 97 percent of reviewers return to the site to plan their next trip.

Priceline has begun setting restrictions for reviewers to those they can verify have recently stayed at the hotel they are trying to review.

comScore has reported that $69 billion was spent last year at online travel sites, up 13 percent from a year ago.