Clive Thompson, over at Wired Magazine has a reasonably good discussion of the importance of genre embedded in his review of the new first-person shooter video game Gears of War. Thompson has an instrumentalist ham-fistedness with passages like this:
Consider the sonnet. It's been around ever since Italian poets invented it in the 13th century, and it's deeply formulaic. But it's never gotten boring, because poets keep on finding surprising new ways to hack it. The Earl of Surrey remixed the sonnet's 14 lines into a new stanzaic structure, turning it into a four-part argument and spurring Shakespeare into an orgy of creativity. Then e e cummings tore the sonnet into tiny shreds, splaying the words across the page while using the rhyming structure to hold each poem together.
Still, he is on to something important about Ciceronian eloquence residing in the familiar. While New Media practitioners and theorists stretch to find the theoretical increments that matter (the mode? the medium? the metaphor?), the rhetors who manage to convince large numbers of people that THEY have something different will end up being the ones who define the important conventions and variations. Game designers are some of the most important rhetors of our time, IMHO.