投资FB必须考虑这个稀释效应//@sylvieluk:@Ricky 看看这个 overhang , “悬货风险”（计算方法为已发出的股票期权+将发出的期权，除以已发行股票数目）-  "And that means that Facebook's stock is likely to face a significant share overhang for the better part of a year—and especially over the next several months."