Visual clutter has unfortunately extended from the digital world into the physical resulting in an interesting evolution of out of home advertising space.  The leader with whom I’ve had good experience is JC Decaux (http://www.jcdecauxna.com/  )  an agency consistently pushing the envelope in the intersection of new technology and out of home advertising.  What used to be static is now dynamic as lighting and movement is integrated into what used to be static small form out of home such as bus shelter advertising.  JC has also put a green spin on out of home with advertising kiosks in Paris which catch and store rain water via roof basins that’s stored in the body of the kiosk and then used to clean and post material on the kiosks with out requiring a water tanker truck to drive around and service the kiosks.  Interactive store windows that sense and interact with the movements of passers-by are exceptionally engaging; check out the weird soundtrack for Diesel in Milan http://www.trendhunter.com/trends/diesel-interactive-store-window-sculpture .  I am intrigued by  the whispering window http://www.youtube.com/watch?v=xxd_CeQPAbY  and the potential it represents for personalized interaction when combined with other technologies, but a high cost may never move it out of a promotional state.  Bluetooth enabled out of home which passes content to passersby as seen at http://news.cnet.com/8301-17938_105-9755102-1.html has the potential to target but also annoy.  Mini did interesting work with RFID enabled billboads that utilize RFID keyfobs and user contributed personalized messages to flash targeted messages as the MINI drives nearby http://www.engadget.com/2007/01/13/mini-usa-rolls-out-rfid-activated-billboards/ .  Really cool, but doesn’t change and gives rise to big brother conspiracy theories.