The Stranger's been using their weblog [slog] like crazy, posting from all of the election parties. But that's not really why I mention it. Throughout the election, many of the writers have used their posts to undermine the paper's editorial endorsements. For instance, several of the writers (including Dan Savage, the paper's editor) have made posts in support of the smoking ban and against Greg Nickels, contrary to their "election control board" recommendations.
I'm not sure if an alt-weekly counts as mainstream media (probably not), but this sort of thing is one of the interesting consequences of what happens when traditionalish journalists keep public weblogs.