The famous Reuters sign in Times square must have a Return on the Intital investment by now. Numerous campaigns and advertising run on the display. Here are a couple of interactive campaigns.
The program includes a Web site, www.TheNewIS.com, where visitors can pose questions about the car to chief engineer Suguya Fukusato, and upload photos to the Web site to enter a sweepstakes to win the car. Some of those photos will be used to form a photo mosaic on the Reuters digital billboard in New York's Times Square, starting Sept. 3. Story - No Pics
In its customary way of going for ever bigger and more different promotions, Nike purchased a build-your-own-shoe media placement on the 23-story-high Reuters sign on the Reuters Building in Times Square. Story and Picture of Reuters Sign
There are many more examples. Oh - here is one by CK you might enjoy. It doesn't involve a digital sign and it's not on the Reuters sign, but it is - some would say - interactive.
This campaign featured a "Live Billboard". See PICTURES.