Earlier this year a mysterious source turned over some e-mails to a Washington Post reporter. The e-mails seemed to indicate that a man with ties to the Republican governor of Maryland, Robert Ehrlich, was spreading rumors about the governor's chief political rival on FreeRepublic.com. The Post wrote a series of articles about the e-mails and the man — a state employee named Joseph Steffen — resigned and apologized to the governor. The Post didn't do any reporting on the source of the e-mails — someone only identified by the Free Republic screen name "MD4Bush" — but it was apparent from...