You've all heard about what happened in Sao Paulo right? That's where the mayor ordered all the billboards removed, saying they were "polluting" his city. What's left is an eerie ghost town with empty skeletal frames all over the place. But the interesting part is the city itself is filling the void.
A colleague of mine told me about the graffiti -- almost a human height-size layer that covers every surface with messages, images and symbols. There's even a guy who does these cool art installations in the sewers, adding a new dimension to the notion of "underground art." She described it as "Everyone talking, everywhere."