In a way, the Net was; only back then it was called the Printing Press. The printing press allowed Luther and his supporters to disseminate his ideas to a wide audience. It also made mass-audience cartoons possible, which enabled Luther to reach a non-literate audience.
(The Protestant and Catholic factions had duelling cartoons; one side presenting Luther as the Ten-Headed Beast of the Apocalypse, and the other portraying the Pope as the Whore of Babylon. That's because Godwin's Law hadn't been invented yet, so they couldn't call each other Nazis).
The invention of printing was a big reason why Luther's ideas took hold and why he wasn't burned at the stake the way John Hus a century or so earlier was.