The Service Nightmare ads, featuring edgy acronyms such as WTF and OMFG aimed at the mayor, are the brainchild of the Working Families Party.
They see it as a way to put pressure on Bloomberg to make good on his campaign promise to help solve problems with the transit system, as the MTA juggles an $800 million budget gap.
"New York City understands sarcasm," party member Dan Cantors said. "It's New York, so we wanted to use some of the MTA's own well-known, well-regarded signage to bring attention to the need for the city to match the state and put in some money to protect student metro cards and other cuts."
The group had hoped to hang the posters underground as part of a four week run that would cost them about $25,000.
But the MTA said no, pointing out the implied obscene language could offend riders and that the ads too closely resembed actual MTA service notices.
The mayor would not comment on the posters, but a spokesperson says the group's anger on this issue is misdirected and that it should be directed to the state.
In the meantime, the signs are not going away. Thousands have been printed and supporters are downloading the image online.
"The word has gotten out for sure," Cantors said. "People are very devoted. People love the transit system and in some ways wish it were better and don't want to see it decline."