Marriott International Inc., Hilton Worldwide Holdings Inc. and InterContinental Hotels Group are using extensive marketing campaigns to claw back business from Expedia Inc., Priceline Group Inc. and other travel-booking sites, which steer customers to hotel properties but also take commissions of up to 30% for each reservation. The chains are starting to treat these sites less as valuable business partners and more as gatekeepers standing between them and their customers. Many large hotel brands are offering lower nightly rates and other perks to loyalty members who book directly through their sites instead of online travel agencies. The industry effort faces an uphill climb, however, as travel portals have become ubiquitous tools for planning a trip. Online travel agencies were responsible for $99 billion worth of world-wide hotel bookings last year, according to travel industry-research group Phocuswright. Get the full story at MarketWatch