Advertising - Online — Online advertising expenses consist primarily of the costs of (1) search engine keyword purchases; (2) referrals from meta-search websites and travel research websites; (3) affiliate programs; (4) banner and pop-up advertisements; and (5) email campaigns. Online advertising expense is generally recognized as incurred. Included in "Accrued expenses and other current liabilities" on the Consolidated Balance Sheets are accrued online advertising liabilities of $130.3 million and $99.6 million at December 31, 2013 and 2012, respectively.
Advertising - Offline — Offline advertising expenses are comprised primarily of costs for television, print, and radio advertising for Booking.com, priceline.com and KAYAK. The Company expenses advertising production costs the first time the advertising takes place.
