SIMPLY STATING facts about Islam can be interesting, but some facts are more interesting than others, and we want to hold peoples' attention when we're talking to them. I have found that the following fact is interesting to people and also helps them see Islam in a new light, and in a memorable way. It helps them think of Islam as not just another religion like any other, but as something unique. When you're talking about Islam, try to work this in somewhere:
Islam is different from other religions in at least one important way: It began at a time and in a place where no empire constrained its spread. In other words, if you start a religion within the Roman Empire, you're going to have certain limitations. The Romans would see any new religion — especially a militant or political religion — as a threat to its power and would make sure you stayed peaceful. A religion that preached tolerance and goodwill toward others might survive, but a violent or militant or political new religion would be quashed immediately.
But Islam had no such restriction when it began, so it could incorporate "conversion by warfare" into its memeplex, and it did. As Aaron Lynch wrote, "The faith provides for a jihad or holy war, which historically led to Islamic rule over whole societies."