A trail of self-praise has followed Citi Bike over the last week. Over 6,000 Citi Bikers pedaled through the city against the Polar Vortex and just yesterday the program announced that it had signed up its 97,000th member.  So why is the docking station outside of the Lillian Wald Houses on Avenue D and East 5th Street so often chock full of bright blue bikes?