Parts I and II of my interview with Prof. Fredriksen are here and here. My thanks to Paula for her time.
PF: What made Jesus different was the impact that he had on his followers — or, more cautiously, what was different was not Jesus, but Jesus' followers. They were so convinced that he was right in his apocalyptic conviction that the Kingdom of God was at hand that (some of them? many? most?) were also convinced, despite their certainty about his death, that he was raised — itself an apocalyptic 'sign' that validated their convictions. The second distinguishing feature about Jesus is that the movement that formed around his memory and mission, within very few years, penetrated diaspora synagogues, where it encountered interested pagans (= "god-fearers"). Their subsequent willingness to relinquish their own native gods and to worship only the god of Israel was itself another confirmation/validation of the movement's message, that the Kingdom of God was at hand. In short, what distinguished Jesus from other apocalyptic teachers was how long his followers were able to continue in their conviction that his prophecy was true. By the time that that prophecy is definitively disconfirmed (say, e.g., by the time of the composition of the Gospel of Luke), it is re-interpreted rather than discredited. By constant post-mortem morphing, Jesus' message had a much longer shelf-life than that of, say, Theudas or the Egyptian.