David Marjanović is a frequent and well respected commentator on Pharyngula. He received his doctorate in paleontology in 2010 but is an expert on many, many subjects. A native of Austria, he is fluent in at least three languages and has an acquaintance with several more. He received the Order of the Molly in September 2007.

He may be referred to by other posters using the initials DDMFM, which stand for Doctor David Mother-Fucking Marjanović. DDMFM is a prolific and erudite poster. Writing a multi-screened reply addressing several individual posters at once is known as Marjanovićing. It is also sometimes used to mean washing a plate by licking it clean. It is essential to include the accent on the final letter when referencing DDMFM, usually accomplished via Windows Character Map.