MD4Bush - Our own "deep throat" who posted on or around the MD mayoral election as well as the national election of last year. He/she seemed to have a detailed knowledge of Maryland politics as well as certain rumors surrounding Mayor Martin O'Malley (MOM). In addtion, this person posted private correspondence (possibly Freepmail) that would damage the reputation of NCPAC (later outed as Steffen of the Ehrlich administration. The posts in question can be found here posted just after 11pm on 2/08. The Sun and Wapo both ran stories the following day breaking the news.
Michael Olesker, Dan Rodricks, David Nitkin , and whoever else at the Baltimore Sun who may be lurking. It should be noted that Nitkin and Olesker were both banned from the statehouse by the governor. A decision that was upheld today.
The Washington Post, including John Wagner, April Witt, Amet R. Paley, Lena H. Sun, David Snyder, Matthew Mosk, Allison Klein, with Mosk doing most of the heavy lifting. The Post made the connection between MD4Bush and NCPAC (Steffen) first, the day after MD4Bush peppered old threads with private messages.
NCPAC - Now known as Joseph Steffen an Ehrlich staffer who had been consistently posting to FR on a variety of topics, including local MD politics. He has since been fired and admitted to the Sun and Wapo that he was NCPAC. His posts are here.
Links to the Atlantic article - So far mention of the article are David Nitkin of the Sun, MD4Bush here on FR, MD state senate President Mike Miller, and a poster on the Sun's forum known as dc925er. I'm sure this list will grow.