29 of 29   By the BQE, Brooklyn   A billboard missing its commercial message has been progressively colonized by street artists, including Obey Giant and Neckface. Note the additional Neckface piece on the building behind the billboard. Photographed by Mike Epstein       "Many street artists are very much in agreement that too much of the city's public space has been sold, given to advertisers," says Wooster Collective's Marc Schiller. "Street art balances the scales a bit. It's like, 'Why is that Gap ad more appropriate than my drawing?'"