With his self-titled, interactive talk-show “The Chris Gethard Show” — which premieres on Fusion May 28 with special guests Abbi Jacobson and Ilana Glazer and musical guest the Front Bottoms — the New York-based comic is building a new kind of talk show in his own image, one that isn’t so much a reaction to the Internet as borne out of it. “TCGS” is a fully immersive experience that severs the boundary between viewer and performer, a show that owes as much to the interactive world of the Web and the absurdist rhythms of improvised comedy as it does to the traditional network talk show. Gethard admits that early Letterman had a huge influence on him, and he shares some of the great man’s subversive, anarchic spirit: a talk-show renegade for the Tumblr generation.