Apparently following the Amazon business strategy model -- maximize build-out investment now, focus on earnings later (maybe...); also see Facebook’s $1.6 billion quarter in charts: how and where it makes money (Quartz)
"After an eight-month roller coaster ride on the public markets, Facebook did well in the fourth quarter of 2012 by aggressively ramping up advertisements aimed at its users, including on mobile phones. In its financial report on Wednesday, it beat expectations, increasing revenue by a handsome 40 percent from the same period a year ago.Facebook Beats Forecasts on Earnings and Revenue - NYTimes.com
But its expenses also climbed rapidly as the company hired engineers and built data centers, causing profit to dip from the last quarter in 2011. With that, Wall Street lost some enthusiasm."