] Clear Channel Communications Inc. plans to begin
] installing digital technology in its outdoor advertising
] over the next two to three years to offer billboards
] whose messages can appeal to different audiences
] depending on the time of the day.

Pittsburgh already has several backlit billboards in particularly high-traffic parts of the city (28S, Forbes off 376 in Oakland, etc). It only makes sense that if they can display arbitrary advertising rotations, why not make it more temporal/demographically targetted?

I think eInk has been offering their technology for bilboards for a while, as well.

What they don't talk about, but would be likely even more effective, would be if they also took to displaying /useful/ data, so that frequent motorists became accustomed to consulting it -- say, weather maps, traffic condition maps, sports scores, whatever. Inject the ads among and between it. Do I smell a business method patent?