On his WTF? podcast, Marc Maron violates the rules of conduct an unctuous talk-show host is supposed to follow. He doesn’t provide softball setups so his comedian guests can test new material; he flatly registers envy, skepticism and sometimes disapproval with his interview subjects; and he won’t let someone off the hook if they trip his laser-sensor bullshit detector — as Carlos Mencia and Gallagher learned to their everlasting regret. But the candor he elicits from guests about the frequently unfunny business of doing comedy has made WTF? a phenomenon — and earned Maron his own Larry Sanders-style hybrid show on IFC. To understand what gives him the cred and the chops to engage everyone from Robin Williams and Judd Apatow to Jack White and Nick Lowe on equal footing, catch his two-night, four-show stand this weekend at Zanies.