These days interactive billboards that "talk" are nothing new, but JetBlue surprised New Yorkers recently with one that actually seemed to be watching people.

The billboard, placed in New York's Chelsea district, invited pedestrians to choose from a variety of topics, press buttons and hear a series of apparently robotic, pre-recorded answers about JetBlue from what appeared to be a video of a crew member on the screen. Nothing particularly exciting about that -- but she then started to comment in real-time on what they were doing, saying and wearing. Eventually the real-life crew member stepped out from behind the screen.

The stunt is part of a series of campaigns from Pearl Media in collaboration with JetBlue's agency Mullen Lowe; others include an interactive game placed in a Florida mall and an installation in New York's meatpacking district, promoting JetBlue flights to Curacao, that invited people to explore the destination via a digital storefront and share photos on Instagram.