Billboards: Blight, or Right?

Arkinet has many excellent photographs of Sao Paolo's former billboards. Could the city's billboard ban work in other cities, and would it be a good idea if so?

Arkinet writes, "Implementing what in current society is such a drastic measure–banning the very lifeblood of the global economy in the public realm–wouldn't be without its imperfections. Assuming the genuine intentions of the 'cleaner city' plan and its implicit commitment to preserving culture, finding means of minimizing ‘visual pollution' is just as logical as countering noise, air, water or any other form of pollution Of course, subjectivity comes into play if some equate visual pollution to aesthetic vibracy for what is a metropolis without the lights and flashing neon signs? New York without Times Square? Tokyo minus Ginza?"