I want to briefly discuss to false memes about Islam - the first is the "swordpoint conversion" one which accuses the Prophet SAW of forcing the world to convert to Islam by force. This is blatant historical polemic. Muhammad SAW in his lifetime only converted Arabia, his ethnic homeland. And that was by the message, not the sword. The image of the Prophet SAW forcing anyone to accept Islam at swordpoint is deeply offensive given that the very concept is antithetical to the spirit of Islam itself:
Ayat 2:256 - "There is no compulsion in religion"
Ayat 109:6, "To you be your Faith, and to me mine."
(click the image to hear a recitation in RM format, courtesy of islam.org)
But it has been a very useful meme in antimuslim polemic.
UPDATE: Bill Allison provides extensive historical context. It's easy to assume that Islam's rapid spread was due to some bloodthirsty rampage, but the geopolitical stage was no less complex back then than it is today. Just like the fall of teh Ottoman Empire, there was a great confluence of events that contributed to Islam's ascension. This is how history winds...