“Graffiti and street art have been highly controversial forms of expression in New York for decades, disdained by art snobs and building superintendents alike. The people who disparage it the most, however, are the city officials who clash with artists and taggers over their creations. Interestingly, this battle has done nothing to diminish street art’s popularity. And now, some experts say, that popularity could do what city official couldn’t: threaten the very essence of this ephemeral work.”