I liked this from Glenn Greenwald:
Adversarial challenges to one’s statements are a vital check on errors and deceit. Clashes of ideas are an irreplaceable instrument for truth-finding. Shielding oneself from such challenges (or just ignoring them) is not only irresponsible and cowardly, but ensures that one can opine without accountability. That’s why bloggers who have an active, smart and critical comment section with which they interact have a major advantage over journalists who hide from critical scrutiny. In all of this, it’s reasonable to exercise some discretion — not all criticisms and/or critics merit attention — but those who avoid any real challenges to their statements (whether politicians, journalists, or pundits) ought to be stigmatized for doing so, and it ought to be viewed as a powerful indictment against their credibility (Ambinder’s post will prompt me to resume efforts to invite onto Salon Radio those who are criticized here and to make note of those who refuse).