Using your phone as a remote control is one of the first uses of phones as a second screen. Users are also using phones to connect to their desktops as a keyboard.
Rosen cites an example of McDonald's Pick n' Play! digital billboard, where users were able to use their smartphones to control a game 'broadcast' in a public place, encouraging consumers to play and interact with the brand. Interaction was verified through geolocation.
Examples like these demonstrate that something 'profound' is going on being able to use mobile and retail within the same space. Could out of home be that fifth screen? asks Rosen.
Sharing your screen is also social currency, and a talking point and buzz for brands.
Screen companion has had most attention from marketers, Rosen added. Consumers use their mobiles to enhance the experience of watching TV. The mobile is a complementary screen, with 77% of those watching TV, using another device.
Rosen discussed how Heineken employed such thinking to reinforce its football sponsorship, integrating a betting/guessing game mobile app into the football game being played on the TV screen. Users were encouraged to guess where goals would come from and how quickly, for example, earning the user points and prizes.
The Watch with Ebay app, where users can shop with their favourite shows was another. 'A great example of what's going on and a great example of contextual advertising', Rosen said.
Overall, the implication of screen companions is that if consumers haven't got the app they won't be able to enjoy the TV show in the same way.