It's an interesting question. By comparison, at the end of 2010 Facebook had about 2,000 +/- employees and $2b in sales for that fiscal year. Twitter is roughly three times overstaffed compared to Facebook.
Do you happen to know how the active user base compares between 2010 Facebook and 2013 Twitter?
Facebook had ~820M MAU at the end of Q4'2010. Twitter has ~230M MAU at the end of Q4'2013.