why do the skins characters have twitter and facebook?

[JY]

For the third generation, E4 seems to have given each main character their own twitter and facebook...yes, not the actors and actresses... but the characters themselves have twitter and facebook with the characters name on it for example, the character Matty Levon's facebook is http://www.facebook.com/mattylevanskins?sk=wall
and they interact with each other on these social networks... they have their own facebook fan pages and twitter sites for their acting and real selves too.

Does anyone know why?>

[LukeGagaMitchel]

Viral marketing

Basically, they bring the fictional world of 'skins' into the real world in an effort to keep fans interested in the show through social networking.