There is no real way to express the value of the public realm of a city. But we can certainly measure its importance to our consumer-driven economy as expressed in outdoor advertising rates. We know that a single billboard along the Gardiner Expressway can cost $16,000 to $39,000 for four weeks, generating $200,000 to $500,000 a year. Clear Channel Outdoor, the largest outdoor advertising company in the U.S., is going on the stock market, and hopes to raise $350 million right off the bat. In 2004, they had a revenue of $2.4 billion. I think those kinds of numbers can give us some perspective on why companies like Clear Channel, Viacom, Pattison, Astral Media, and EUCAN all want to piggyback on city infrastructure. It also highlights the financial capabilities they can use to lobby politicians.