Jack didn't know mark until he moved to LA to live with Bob and Wade. They told mark about Jack so he could watch some of his videos before arriving. Mark got excited to see him and texted him using Bob's phone to say he would pick him up. Jack questioned who this was and got excited that it was the person he recently found on YouTube that interested him. Once Jack got to LA something was suspicious between Jack and mark. They were living together and they were basically inseparable. WARNING: it may be overloaded by cute and some possible smut.