"We do not know how to describe the audience for new media. 'Audience' fits the activities of listening and watching. New information and communication technologies open up more active and diverse modes of engagement with media - playing, surfing, searching, chatting and downloading." (Livingstone 2005, 44)
An interesting article addressing this idea is "Dude, Where's my Audience". They suggest that traditional media measurements and tracking aren't keeping up with new habits such as time-shifting programs and multi-tasking (sitting with one eye on the TV with another on the laptop in front of you). They suggest that because media measurements are failing to measure this, the new media audience is probably being vastly underestimated.
References:
Banks, J. (2002). "Gamers as Co-Creators: Enlisting the Virtual Audience - A Report From the Net Face," in M. Balnaves, T. O'Regan and J. Sternberg (eds) Mobilising the Audience, St Lucia: University of Queensland Press.
Livingstone, S. (2005). "Media Audiences, Interpreters and Users," in M. Gillespie (ed.) Media Audiences, Maidenhead: Open University Press.
TheAge.com. (2007). Dude, Where's My Audience? Retrieved April 15, 2008, from http://www.theage.com.au/news/web/dude-wheres-my-audience/2007/07/24/1185043119701.html?page=fullpage