Did they added monetization strategies into this app (ads, sponsored stories, etc)? I'm not an iOS user, but after their harsh stock decline I would've expected to see aggressive monetization on the mobile app/web.
Facebook are making currently making $183M a year off mobile & they haven't rolled them out worldwide yet either.
They were appearing for me in the old iOS app & are only be shown every 150 or so (at the moment in the tests they are performing) which has been confirmed by Facebook's CFO David Ebersman who said Facebook are "being very careful about the volume of sponsored stories in the news feed because it’s so core to the user experience."