Lawrence Lessig is a constant source of powerful ideas, but his newest wiki, the Anti-Lessig Reader, is a rather impressive attempt at inviting, as he puts it, "the other side of the story". What better way to get away from the echo than opening the door yourself and inviting in new voices.
So, how can we take this example and use it with students? A wikified debate seems like a logical first step. Small groups of students could take various aspects of a complicated issue and, using the wiki, share the arguments and work toward understanding the depth of the issue.
Of course, given the ease of editing, I can already see students "helpfully" making changes to the opposition's information. What great opportunities for discussing ethics, integrity, and respect for multiple view points.