Some dirty asshat named Ronald Puskin* is threatening to reveal Atrios's Secret Identity or worse, sue him. Now, as we all know from Superman Comic Books, a superhero's true identity is a sacred thing and you'd have to be a real twisted bastard to try and out him for cheep politcal gains. Something on the order of Lex Luthor or Karl Rove (but then, I'm just repeating myself).
It seems Atrios implied that Mr. Puskin is a stalker. Thing is. Mr. Puskin actually calls himself a stalker. To make matters all the more surreal, the threat of litigation isn't actually over anything Atrios said but rather something someone in the comments section said that might be interpreted as Libel. If you wouldn't know satire if it started fellating your big toe. Or if you were, say a despicable, overly litigious hack who very likely molests goats and possibly children as well.
*I changed his name so that Donald Luskin wouldn't sue me for libel.