McLuhan Reading

I am not quite sure what to make of the reading. I liked some of the interesting facts regarding Napoleon's fear of newspapers, or the "money medium" in 17thC Japan. But I got the feeling that this chapter was too broad for its own good. One thought I had: According to McLuhan, the medium became the message is the electronic age. So, before the lightbulb existed, people believed that the "content" was the message. Well, as I read that paragraph, I imagined a Medieval church service. I wonder if the people is the pews believed that the content was the message, or whatever the priest talking about, or if God himself was the medium. A neat relationship, no? If "the medium is the message", how does that apply to religion.