Integrating mobile phones with digital signage just got more interesting and possibly even more profitable. Digital signage could now be the "signpost" that brings the user to the details on their mobile app, and the mobile app serves up that advertising sponsored detail to the end user. No more having to prove who saw what as they walked by a large format display and this approach lessens the anxiety that every digital signage vendor feels about giving away too much to non-revenue contributing mobile applications and displays. The mobile phone could now become the primary advertising sponsor of the large format display. Interesting role reversal... via Apple iAd brings ads, cash money to third-party iPhone apps -- Engadget.