Rock, Paper, Stone: The Biz Stone Guide to Independent Publishing: "With blogging and other microcontent management software, you can often add team members and allow others to post to your site. Adding the team members makes for a more diverse coverage of whatever topic your group blog is focused on. The seven person strong blog The End of Free is a great example of a team blog that works."

Thanks! Update: especially considering that some people seem to think there's no such thing as a collaborative blog.