ook-ads-in-the-next-few-months%2F/918F/5753895284631425024/EMLnus_share-F1- 2/?hs=false&tok=0YXc4ZHJdfYIM1&trackinfo=updateld%2C5753895284631425024> Andrew Bosworth, Facebook's head of engineering for ads, shows reduced number of ad formats. Under pressure to speed up its advertising growth, Facebook has announc