recoverable, the carrying amount of such assets is reduced to fair value. We have not recorded any such impairment charge during the years presented. unamortized balance would be amortized over the revised estimated useful life. through their relationships with advertising agencies, based on the number of impressions delivered or the number of clicks made by our users. We recognize revenue from the delivery of click-based ads in the period in which a user clicks on the content. We recognize revenue from the display of impression-based ads in the contracted period in which the impressions are delivered. Impressions are considered delivered when an ad is displayed to users. The number of ads we show is subject to methodological changes as we continue to evolve our ads business and the structure of our ads products. Whether we count the initial display only or every display of an ad as an impression is dependent on where the ad is displayed. For example, an individual ad in News Feed that is purchased on an impression basis may be displayed to users more than once during a day; however, only the initial display of the ad is considered an impression, regardless of how many times the ad is actually displayed within the News Feed. available on our website. We receive a fee from our Platform developers when users make purchases from our Platform developers using our Payments infrastructure. We recognize revenue net of amounts remitted to our Platform developers. We have mandated the use of our Payments infrastructure for game apps on Facebook, and fees related to Payments are generated almost exclusively from games. Cumulatively to date, games from Zynga have generated the majority of our payments and other fees revenue. However, Zynga's contribution to our payments and other fees revenue has decreased over time and this trend may continue. Our other fees revenue consists primarily of user Promoted Posts and, to a lesser extent, Facebook Gifts revenue, and has been immaterial in recent periods. and server equipment depreciation, facility and server equipment rent expense, energy and bandwidth costs, support and maintenance costs, and salaries, benefits, and share-based compensation for employees on our operations teams. Cost of revenue also includes credit card and other transaction fees related to processing customer transactions. building new products as well as improving existing products. We expense all of our research and development costs as they are incurred. |