Facebook's (FB) mobile ad sales jumped 41% Q/Q and roughly 4x Y/Y in seasonally strong Q4 to $1.24B, a figure that soundly beat many analyst forecasts. Mobile accounted for 53% of ad sales, up from 49% in Q3 and 23% a year ago.
Total ad sales rose 76% Y/Y (an acceleration from Q3's 66% clip) to $2.34B. Payments revenue (important for ZNGA) totaled $241M, up from $218M in Q3 and favorable to a year-ago level of $256M, given 4 months were counted last year.
Facebook ended Q4 with 1.23B monthly active users (MAUs), +3% Q/Q and +16% Y/Y. Mobile MAUs grew 8% Q/Q and 39% Y/Y to 945M (77% of total MAUs). Mobile-only MAUs (a lot of them are in emerging markets) rose 17% Q/Q and 89% Y/Y to 296M (24% of total MAUs).
Costs/expenses rose 37% Y/Y, a slowdown from Q3's 45% clip and well below revenue growth of 63%. R&D spend +37% to $408M, sales/marketing +51% to $292M.
Op. margin rose to an eye-popping 56% from 46% a year ago. Capex (often strong in Q4) was a hefty $483M, up from $284M in Q3.