The Citi bikes are everywhere now up to 86th st.. Even some on 5th avenue next to the Central Park (72nd and 79th st.). The sight of so many Citi bikes makes me feel safer riding bike, knowing that drivers are becoming more aware of the cyclists sharing the road with them.
(To a much lesser degree, more people on the bikes may also mean less people driving for short trips, though I assume in Manhattan most riding the Citi bikes would have taken public transportation if there were no Citi bikes.)