on Ad Age, their is a video featuring DC comics VP of advertising, John Cunningham saying that because comic book fans are early adopters of tech their market will be hit with a large number of their fan base going to things like the kindle or other ebook readers to get their comics.
It's clear by listening to him that he is both fearful of the ideal of losing their market...but honestly if the comic book publishers keep up with the new mediums they can SELL their comics they really shouldn't be worried.
That right instead of thinking this is doom for DC comics and other publishers I think this is time (past time really) that more publishers put out versions of their comics for things like the kindle. it's a new market that will lead to new sells as well as keep current sells study (every month the comic book market loose more and more fans, this can be a way to stop the lose or shrink it)
and if itunes is an example people will pay for content online