At long last the NYC subway system enters the 20th century! It seems that the MTA will be installing message boards to tell riders when the next train is coming:
MTA To Install Message Boards To Tell Riders When To Expect Next Train
The days of waiting on the subway platform not knowing when the next train will come will soon be a thing of the past. The Transit Authority is installing new electronic message boards that will give subway riders a countdown to the next train arrival.
I mostly taking the J line these days so this won't be an immediate plus for me, but I think in the end this will be a good thing for subway riders.