It would be the most recent one, in which I call a quoted blogger (NOT a DUer...a blogger) who smears all unhappy progressives as "white narcissists" who "have no real contact with the poor" an "ignorant bigot". Considering that I am a poor person myself and come from a mixed-race family, I was very much offended by those broadbrush attacks. Frankly, it WAS an ignorant and bigoted article. It's insulting (and flat-out incorrect) to claim that the only people who are unhappy with the way this nation is being governed are well-off, privileged white people. So far as I know, it is not against the rules to personally attack outside bloggers who are quoted here. People do it all the time to other bloggers (Nate Silver, Jane Hamsher, Glenn Greenwald, etc.)
Edit: Sorry, I forgot to include a link to the context thread.
http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=439&topic_id=1843334&mesg_id=1843334