Old Navy's new ad campaign is a great example of this. Their new music-centric campaign delivers its message through original lyrics in a pop tune that's searchable with the Shazam app. When consumers use Shazam to identify any of the songs, they'll also see current deals, new looks and styling tips pop up on their screens.
In a clever twist, they used the campaign switch as a way to connect with consumers by "leaking" the "audition tapes" of the previous campaign's principle characters, the Old Navy Mannequins on youtube.
I love that they turned something as basic as a new ad campaign into an opportunity to promote themselves.