Of course you don’t have to read an author’s work to have to deal with their influence. Major figures like Faulkner, Pynchon, Bolaño, and David Foster Wallace cast such a wide shadow that they’re a liability for every writer today. You can’t write except by writing against them, trying to get out from under, not least because even if you haven’t read them your potential readers have, so the risk of having failed to negotiate their influence is unavoidable.
In the Internet age, it is not unlikely to feel the influence of an author without even having read him or her. Over at Electric Literature, David Rice takes a look at the phenomenon of “shadow influences.”