So the argument begins with traditional composition's underlying premise. It is, in the end, not so very different from the premise that historically has allowed English departments to suggest that their majors prepared students to be good writers in some general way.
That is, basically, that learning to write the humanistic essay is equated with learning to write in general. 50-100 years ago, in a more homogeneous campus culture, that premise might have made sense. It was still a fantasy, but a more realistic fantasy. That is, it was like fantasizing about having a triste with your neighbor. It probably wouldn't come to pass. You'd probably regret it if it did. But under the right circumstances, with enough wine, who knows? Today, this fantasy is more like fantasizing about having a triste with a movie star. As such it is that much more enticing because it is so unlikely. The specter of the fantasy coming true and having to deal with the consequences never really enters one's mind.
So the project of composition, like some many grand narrative projects of modernity, never really gets off the ground. One could still have introducing students to the composition of the humanistic essay as a goal of FYC, but one can no longer imagine that it serves any grander purpose than teaching them to write in a genre most of them will never write again. Of course, general education courses face these problems across the board. General education itself is a failed project of modernity. That doesn't mean that students can't learn in such courses or that they aren't worth asking students to take. It means that conceiving of these courses as resting upon the fables of modernity is unsustainable.
What does one take away from Intro to Biology? or Intro to Psych? or Western Civ I? Some discrete bits of knowledge I suppose (most of which fades with time)? Some general appreciation for what folks do "over there"? Maybe you get interested in a field you never knew and find your major. Perhaps that's the point, to sample from the tasting menu before ordering. In any case, FYC is just as valid as any of these as an introduction to rhetoric.
And we could leave it at that.
However I do think that composition has potentially more to offer. Composition can be a place where students take up the rhetorical methods they learn not only to study others' writing but to examine their own writing practices, and (potentially) to develop their own writing (process). Of course we cannot promise this last piece as it points to what students will do following FYC. But we can give them the tools to take advantage of this opportunity.
And here is where I see digital media as integral. We cannot know what kinds of writing students will be asked to do in other classes after the leave us. Maybe a lot. Maybe very little. Perhaps it will resemble humanistic writing. Maybe they will be English majors (it happens from time to time.). What we can know with a higher degree of certainty is that they will write for online spaces. Of course this writing is often very, very short and highly informal. But it is the one writing practice they actually elect to pursue.
My suggestion is that by incorporating digital composition into FYC we can make connections between their current elective writing practices and other writing practices that they might choose to adopt. I'm not so naive as to imagine that more than a few students will make that choice. But if we still see it as our goal to give students an opportunity to develop a writing practice then I think that's our best chance. I could also argue that studying digital media is a worthwhile inclusion in a course the purports to introduce students to rhetoric as general education but really I think that's secondary to the purpose I've just described.
Ultimately, in a field where almost everything is uncertain, I think the one thing we could agree on is that if students are to become better writers, their best chance is if they can develop a writing practice that extends beyond the writing they are required to do for their coursework. Instilling a digital writing practice, in my mind, is the best available strategy for making that happen.