Your cellphone design provides an important way to say who they are -apparently. A recent New York Times article talked about how manufacturers are managing to charge huge prices for devices which look cool and make their owners appear smart and/or exclusive -“like a movie star.”
“…the sleek Motorola Razr V3 cellphone first hit the stores just over two years ago, it carried the price tag of a must-have status symbol: $500. Now? About $30 with a two-year service contract.”

Today’s invention is one more attempt to endow such products with this ‘wow’ factor, but without having to pay for fancy (costly) technical innovations they don’t actually need.
This simple mechanism (which is actually part of a booklight) has a couple more links than the standard clamshell design and these seem to imbue it with a significantly more complex, lifelike movement.
Imagine the social effect of being the first with a fold-out cellphone mouthpiece (suitable sound effects during unfolding would enhance this impact further). Devices like this, with more degrees of freedom, also allow for many more interesting unfolding processes than do simpler ones.
Of course, once you start to get into the realm of powered, multilink mechanisms, the possibility of a cellphone-as-robot emerges. Just think how cool it would be for your cellphone to ‘walk’ to you from the next room when there was an incoming call.