Apropos of my previous post, Think Progress' NetTrends '08 is a site that has compiled a matrix of all of the social media vehicles currently in use by candidates from both parties. As of today, no Republican candidates are blogging, but this could change. NetTrends '08 is actively soliciting additional links.
I am not familiar with Think Progress, but according to the organization's web site: "Think Progress is a project of the Center for American Progress Action Fund, ... (which) is a nonpartisan organization. With the blog, CAPAF seeks to provide a forum that advances progressive ideas and policies."