The billboard is listening. [1]
"In an advertising ploy right out of Steven Spielberg's "Minority Report," electronic billboards in the Bay Area and Sacramento are being equipped to profile commuters as they whiz by -- and then instantly personalize freeway ads based on the wealth and habits of those drivers."
These billboards key into the radio station a driver is listening to and then tailor the ads to the suggested demographic.
Links:
[1] http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2002/12/22/MN242772.DTL
[2] http://technorati.com/tag/advertising news